Introduction

NOTE: For Specifications with illustrations, make reference to ENGINE SPECIFICATIONS FOR G342 ENGINE, Form No. REG01526. If the Specifications in Form No. REG01526 are not the same as in the Systems Operation and the Testing and Adjusting, look at the printing date on the back cover of each book. Use the Specifications given in the book with the latest date.

Troubleshooting

Troubleshooting can be difficult. The TROUBLESHOOTING INDEX gives a list of possible problems. To make a repair to a problem, make reference to the cause and corrections on the pages that follow.

This list of problems, causes, and corrections, will only give an indication of where a possible problem can be, and what repairs are needed. Normally, more or other repair work is needed beyond the recommendations in the list. Remember that a problem is not normally caused only by one part, but by the relation of one part with other parts. This list is only a guide and can not give all possible problems and corrections. The serviceman must find the problem and its source, then make the necessary repairs.

Troubleshooting Index

1. Engine Crankshaft Will Not Turn When Start Switch is On.

2. Engine Will Not Start.

3. Misfiring or Running Rough.

4. Stall at Low rpm.

5. Sudden Changes In Engine Speed.

6. Not Enough Power.

7. Too Much Vibration.

8. Loud Combustion Noise (Knock).

9. Loud Noise (Clicking) From Valve Compartment.

10. Oil In Cooling System.

11. Mechanical Noise (Knock) In Engine.

12. Gas Comsumption Too High.

13. Loud Noise From Valves or Valve Drive Components.

14. Little Movement of Rocker Arm and Too Much Valve Clearance.

15. Valve Rotocoil or Spring Lock is Free.

16. Oil at the Exhaust.

17. Little or No Valve Clearance.

18. Engine Has Early Wear.

19. Coolant in Lubrication Oil.

20. Exhaust Temperature is Too High.

21. Too Much White or Blue Smoke.

22. Engine Has Low Oil Pressure.

23. Engine Uses Too Much Lubrication Oil.

24. Engine Coolant Is Too Hot.

25. Starter Motor Does Not Turn.

26. Alternator Gives No Charge.

27. Alternator Charge Rate Is Low or Not Regular.

28. Alternator Charge Too High.

29. Alternator Has Noise.

30. Solenoid Does Not Stop Engine.

31. Short Spark Plug Life.

32. Preignition.

33. Detonation.

34. Gas Supply Line Shutoff Valve Failure.

35. Instrument Panel Gauge Switches Do Not Stop Engine.

36. Instrument Panel Gauge Switches Prevent Engine Start.

37. Failure of Overspeed Contactor Switch to Shutoff Engine.

38. Overspeed Contactor Stops Engine at Low Speed.

39. Air Starting Motor Turns Slowly.

40. Troubleshooting Solid State Magneto. (Fairbanks Morse)

40A. Missing on One or More Cylinders.

40B. Engine Dead and Has No Spark.

41. Troubleshooting Solid State Magneto. (Altronic)

41A. Missing on One or More Cylinders.

41B. Engine Dead and Has No Spark.

Engine Crankshaft Will Not Turn When Start Switch Is On.

Engine Will Not Start

Misfiring Or Running Rough

Stall At Low RPM

Sudden Changes In Engine Speed

Not Enough Power

Too Much Vibration

Loud Combustion Noise (Knock)

Loud Noise (Clicking) From Valve Compartment

Oil In Cooling System

Mechanical Noise (Knock) In Engine

Gas Consumption Too High

Loud Noise From Valves Or Valve Drive Components

Little Movement Of Rocker Arm And Too Much Valve Clearance

Valve Rotocoil Or Spring Lock Is Free

Oil At The Exhaust

Little Or No Valve Clearance

Engine Has Early Wear

Coolant In Lubrication Oil

Exhaust Temperature Is Too High

Too Much White Or Blue Smoke

Engine Has Low Oil Pressure

Engine Uses Too Much Lubrication Oil

Engine Coolant Is Too Hot

Starter Motor Does Not Turn

Alternator Gives No Charge

Alternator Charge Rate Is Low Or Not Regular

Alternator Charge Too High (As Shown By Battery Needs Too Much Water)

Alternator Has Noise

Solenoid Does Not Stop Engine

Short Spark Plug Life

Preignition

Detonation

Gas Supply Line Shutoff Valve Failure

Instrument Panel Gauge Switches Do Not Stop Engine

Instrument Panel Gauge Switches Prevent Engine Start

Failure Of Overspeed Contactor Switch to Shutoff Engine

Overspeed Contactor Stops Engine At Low Speed

Air Starting Motor Turns Slowly

Troubleshooting Solid State Magneto (Fairbanks Morse)

Show/hide table

NOTICE
Be sure to reconnect "H" lead to shutdown circuit after repairs are made. Failure to do so will leave the engine unprotected and damage could result.

Troubleshooting Solid State Magneto (Altronic)

Show/hide table

NOTICE
Be sure to reconnect the wire to the magnetic switch and the connector to the magneto after the repairs are made.

Ignition System

To make a test of the magneto on the engine, check the condition (intensity) of the spark at the spark plug. Remember that the condition of the instrument panel components: magnetic switch, stop switch, oil pressure gauge and water temperature gauge have an effect on the output of the magneto. A defect in, or an activated overspeed shutoff contact or gas line solenoid valve can cause an indication of a defect in the magneto.

A test of the magneto off the engine can be used to find a defect in the electrical components. The 2P2340 Magneto Test Bench is used to make the tests. Special Instruction Form No. GEG02059 gives the complete test procedure.

Finding Top Center Compression Position For No. 1 Piston

2P8300 Engine Turning Tool Group.

No. 1 piston at top center (TC) on the compression stroke is the starting point for all timing procedures.

1. Remove valve cover (1) at the front of the engine.

LOCATION OF VALVE COVER
1. Valve cover.

TIMING MARK COVER
2. Cover.

2. Remove cover (2) from the top of the housing for the flywheel.

TIMING MARKS ON FLYWHEEL
3. Pointer.

3. Turn the flywheel in the direction of engine rotation until No. 1 piston is at top center (TC) on the compression stroke. An indication is by pointer (3).

4. Look at the valves for No. 1 cylinder (the two valves at the front of the engine). The intake valve and exhaust valve for No. 1 cylinder must be closed.

5. If the intake and exhaust valves for No. 1 cylinder are not closed, turn the flywheel in the direction of engine rotation 360°. If both valves are now closed, this is top center (TC) compression position for No. 1 piston.

ENGINE TURNING TOOLS
4. 2P8294 Housing. 5. 2P8299 Pinion.

NOTE: If the flywheel is turned too far, turn it in the other direction a minimum of 60°, then turn the flywheel in the direction of engine rotation until No. 1 piston is at top center (TC) on compression stroke.

Timing Of Magneto To Engine (Spark Gap)

2P8300 Engine Turning Tool Group.

1. Turn the flywheel in direction of engine rotation until the No. 1 piston is coming up on the compression stroke. See subject Finding Top Center Compression Position for No. 1 Piston.

2. Turn the flywheel until the desired timing mark is directly under the flywheel pointer. See the Chart NO. 1 CYLINDER TIMING ANGLES (SPARK CAP) for the correct operating conditions.

3. Put the magneto drive slot (1) in vertical position as shown in illustration. The drive coupling can be pulled to the rear, put in the correct position, and then pushed forward to engage with the gear teeth.

DRIVE TANG AND SLOT POSITION (Seen from Rear of Engine)
1. Drive tang and slot.

4. Remove the timing nut and turn the magneto drive until the timing hole (2) is in the center of the hole (3).

5. Install the magneto. The drive tang and slot will engage.

6. Make the final timing adjustment by turning the magneto at the drive housing mounting. Use a timing light with the engine running to check the alignment of the correct mark on the flywheel with the pointer.

MAGNETO TIMING
2. Timing hole. 3. Hole in magneto housing for timing nut.

Firing Order

The firing order (ignition sequence) is 1, 5, 3, 6, 2, 4. The direction of the arrows in the illustration show the rotation of the magneto distributor disc (A) and the drive tang (B) as seen from the end cap cover (rear of engine).

DIAGRAM OF MAGNETO NUMBERING (Seen from rear of engine)
A. Magneto distributor disc. B. Drive tang.

Magneto Point Gap

Make the magneto point gap setting to .017 in. (0.43 mm).

Magneto Edge Gap

The maximum ignition discharge is a result of breaking the primary circuit at the exact point in time that the voltage in the primary circuit is at the maximum value. At this point the contact points are just starting to open.

Field Method

When the setting of the edge gap is needed and cannot be made with the use of 2P2340 Magneto Test Bench, a temporary setting can be made.

1. Check the contact points and make an adjustment to the proper gap, if needed.

2. Remove the impulse coupling.

3. Turn the rotor shaft so the keyway is up. Then turn the shaft approximately 15° in the direction of rotation.

POSITION OF SHAFT (Counterclockwise Magneto)

4. Look at magneto from the drive end. Remove the set screw and put a 1/8 in. (3.175 mm) diameter rod (4) in the right timing hole (3). The left hole is used for clockwise rotation magnetos. Do not use it.

5. Loosen screws (1) for the support plate (2).

EDGE GAP ADJUSTMENT (Counterclockwise Magneto)
1. Screws for the support plate. 2. Support plate. 3. Timing holes. 4. Rod.

6. Push rod (4) in until it is in contact with the rotor. Turn the rotor shaft in the direction opposite the normal rotation until the rod is tight between the rotor pole shoe and housing field.

7. With the rotor in this position, move the plate (2) either left or right until the contact points start to open. Tighten the screws (1) for the support plate.

8. Install the impulse coupling.

Shop Method

2P2340 Magneto Test Bench.

The method of making the edge gap setting with the most accuracy is with the 2P2340 Magneto Test Bench. The complete instructions for making the setting are in Special Instruction Form No. GEG02059. The correct speed for rotation of the magneto is 1800 rpm.

Brush Spring Adjustment

Each time service is done on a magneto, a check must be made of the distance between the distributor block (3) and the face of the distributor disc (5). The correct gap gives the correct pressure on the brush and spring assembly (6). Remove the timing bolt and put a drill rod (4) between distributor block (3) and distributor disc (5). The clearance is .156 to .219 in. (3.96 to 5.56 mm).

To make an increase in clearance use additional gaskets (2) for the end cap cover. To make a decrease in clearance use number 10 washers between the distributor block (3) and end cap cover (1).

MAKING A CHECK OF THE BRUSH SPRING ADJUSTMENT
1. End cap cover. 2. Gasket for the end cap cover. 3. Distributor block. 4. Drill rod. 5. Distributor disc. 6. Brush and spring assembly.

Timing Of Magneto To Engine (Solid State Fairbanks Morse)

1. Turn the crankshaft in the direction of engine rotation until the No. 1 piston is coming up on the compression stroke. See the subject Finding Top Center Compression Position for the No. 1 Piston.

2. Turn the crankshaft until the desired timing mark is directly under the flywheel pointer. See the charts No. 1 Cylinder Timing Angles (Fairbanks Morse Solid State Magneto) for the correct operating conditions.

NOTE: After top center (ATC) timing with the engine stopped is needed under some conditions. When flywheels with no ATC marks are found, put marks on the outside diameter of the flywheel by using the same dimensions from the marks now on the flywheel.

DRIVE TANG AND SLOT POSITION (Viewed from the rear of the engine)

3. Put the magneto drive slot in the position shown in the illustration. The drive coupling can be pulled to the rear, put in the correct position and then pushed forward to engage with the gear teeth.

4. Remove the timing nut and turn the magneto drive until the timing hole (1) in the gear is in the center of the hole (2).

LOCATION OF TIMING HOLE
1. Timing hole in gear. 2. Hole in magneto housing.

5. Install the magneto. The drive tang and slot will engage.

6. Make the last timing adjustment with the engine running at the rated speed. See the FUEL SETTING INFORMATION. Use a timing light to check the alignment of the correct mark on the flywheel with the pointer. Turn the magneto at the drive housing mounting until the mark and pointer are in alignment.

NOTE: Timing must NOT be made at low idle because of the timing advance in the magneto.

Firing Order

The firing order (ignition sequence) is 1, 5, 3, 6, 2, 4. The direction of the arrows in the illustration shows the rotation of the pulser rotor assembly (1) and the drive tang (2) as seen from the rear of the engine.

ROTATION OF PULSER ROTOR ASSEMBLY AND DRIVE TANG
1. Pulser rotor assembly. 2. Drive tang.

Timing Of Magneto To Engine (Solid State Altronic)

1. Turn the crankshaft in the direction of engine rotation until the No. 1 piston is coming up on the compression stroke. See the subject Finding Top Center Compression Position for the No. 1 Piston.

2. Turn the crankshaft until the desired timing mark is directly under the flywheel pointer. See the charts No. 1 Cylinder Timing Angles (Altronic Solid State Magneto) for the correct operating conditions.

MAGNETO TIMING MARKS (Typical Example)
1. Timing marks.

3. The magneto timing marks (1) must be in alignment when the No. 1 piston is at the correct BTC position.

4. If not correct, remove the magneto from the engine.

MAGNETO DRIVE TANG
2. Drive tang.

5. Put timing marks (1) in the correct position with drive tang (2) positioned as shown.

6. Position the magneto drive slots in proper position for timing. The drive coupling can be pulled out, then positioned and pushed in for engagement.

7. Install the magneto. The drive tang and slot will engage.

8. Make final timing adjustment by rotating the magneto at the drive housing mounting and with the use of a timing light when the engine is running at rated speed.

Ignition Transformers

See the subject WIRING DIAGRAM in the SYSTEMS OPERATION section for the way the transformers are connected to the magneto.

Spark Plugs and Adapters

8S7227 Wrench.8H3538 Socket.1P1790 Firing Indicator.1P7424 Spark Plug Socket.

If the spark plug adapter does not have a covered seat, water leakage or detonation and preignition can be the result. Adapters are installed and removed with an 8S7227 Wrench and 8H3538 Socket.

Voltage to cause the spark will change with the spark plug condition and engine load. A new spark plug in an engine at low idle will take 3,000 to 6,000 volts. At full load, this voltage will be 8,000 to 10,000 volts. When the gap of the spark plug needs adjustment the voltage needed will be over 10,000 volts. Voltage needed will go higher if plug gap adjustment is not made. Spark plugs start to cause the engine to run rough (fire erratically) when the spark plug voltage needs go higher than 10,000 volts.

Spark plug gap must be kept at .014 ± .001 in. (0.36 ± 0.03 mm). The use of 1P1790 Firing Indicator is an aid for finding ignition problems. Follow the instructions that come with the tool.

Put liquid soap on the seat groove of adapter (1) and seal. Install the adapter into cylinder head and tighten to a torque of 150 ± 10 lb. ft. (205 ± 14 N·m). Spark plugs (3) must be installed to a torque of 26 ± 4 lb. ft. (36 ± 5 N·m) with 1P7424 Spark Plug Socket (4).

SPARK PLUG INSTALLATION
1. Adapter. 2. 3/8 in. Drive extension. 3. Spark plug. 4. 1P7424 Spark Plug Socket.

Adjustment Of Gauge Contact Point

The adjustment of the contact for the pressure gauge for oil is correct when the engine is stopped at 8 psi (55 kPa) oil pressure. The correct adjustment of the gauge for water temperature is when the engine is stopped at 210°F (99°C).

Adjustment of the gauges is made with a small hollow head screw wrench.

WATER TEMPERATURE GAUGE
1. Adjustment screw.

OIL PRESSURE GAUGE
2. Adjustment screw.

Gas, Air Inlet And Exhaust System

Restriction Of Air Inlet And Exhaust

There will be a reduction of horsepower and efficiency of the engine if there is a restriction of the air inlet or exhaust system.

Air flow through the air cleaner must not have a restriction of more than 15 in. (381 mm) of water difference in pressure.

Back pressure from the exhaust (pressure difference measurement between exhaust outlet elbow and atmosphere) must not be more than 34 in. (864 mm) for naturally aspirated and 27 in. (686 mm) for turbocharged engines measured between the turbocharger outlet and atmosphere.

Crankcase (Crankshaft Compartment) Pressure

Broken or damaged pistons or piston rings can be the cause of too much pressure in the crankcase. This condition will cause the engine to run rough. There will also be more than the normal amount of fumes coming from the crankcase breather. This crankcase pressure can also cause the element for the crankcase breather to have a restriction in a very short time. It can also be the cause of oil leakage at gaskets and seals.

Compression

2P8300 Engine Turning Tool Group.

An engine that runs rough can have a leak at the valves, or valves that need adjustment. Run the engine at the speed that gives rough running. To find a cylinder that has low compression or does not have good ignition, remove spark plug wires one at a time. This will stop the flow of current to that cylinder. Do this for each cylinder until a removed wire is found that makes no difference in engine rough running. Be sure to install the wire for the spark plug after each cylinder test before the next wire is removed. This test can also be an indication that the spark plug is bad, so more checking of the cylinder will be needed.

Conditions of the valves, valve seats, pistons, piston rings and cylinder liners can be tested by putting air pressure in the cylinder. Special Instruction Form No. GMG00694 gives instructions for the test procedure. It also gives the list of parts needed from Parts Department to make the test.

This test is a fast method of finding the cause of compression loss in a cylinder. Removal of the head and inspection of the valves and valve seats if necessary to find those small defects that do not normally cause a problem. Repair of these problems is normally done when reconditioning is done on the engine.

Carburetor

The carburetor and governor linkage adjustment is given in the subject GOVERNOR.

Turn the power mixture adjustment to center between "R" (rich) and "L" (lean). Make fuel mixture adjustments by changing the gas pressure from the line pressure regulator. See the subject GAS PRESSURE REGULATOR ADJUSTMENTS.

Turn idle adjustment screw (1) four full turns open (from the closed position).

CARBURETOR ADJUSTMENTS
1. Idle adjustment screw. 2. Throttle stop screw.

Turn throttle stop screw (2), to obtain desired idle speed. See FUEL SETTING INFORMATION for low idle rpm.

Adjustment to the Low Idle (Engine Not Operating)

1. Disconnect governor linkage at the throttle shaft lever (2).

2. Turn the screw (1) out until the throttle will close before the screw makes contact with the stop. Slot (3) in the end of the throttle shaft shows the position of the throttle plate.

3. Turn the stop screw (1) so it will just make contact with the stop while the throttle plate is closed.

THROTTLE VALVE SYNCHRONIZATION
1. Throttle stop screw for low idle. 2. Throttle shaft lever. 3. Slot.

4. Move the control lever for the governor to the OFF position.

5. Make adjustments to the length of the linkage between governor and carburetor until both connections can be made while the throttle plate is completely closed, and the governor weight fully closed.

6. Connect the linkage to throttle shaft lever (2).

7. Start the engine and make a setting to the throttle stop screw (1) for the low idle.

Performance Evaluation

When an engine has no power, it is desirable to make a quick check with an instrument to find the approximate horsepower.

Use the 4S6553 Instrument Group to check engine rpm and the pressure in the inlet manifold. This instrument group has a tachometer for reading the engine rpm and a gauge for reading the pressure in the inlet manifold. Differential pressure gauges are used to make measurements of the gas pressure and air inlet pressure. Special Instruction Form No. SEHS7341 is with the tool group and gives instructions for the test procedures.

Correct engine operating adjustments must be made to get the correct results from the instruments and tests.

Correct analysis can be made of the engine operating efficiency by a check of the pressure of the inlet manifold and a comparison of that pressure with the information in the FUEL SETTING INFORMATION. This test is used if the engine horsepower is too low, but with no other condition of engine problem.

4S6553 INSTRUMENT GROUP
1. 4S6992 Differential Pressure Gauges. 2. Zero adjustment screw. 3. Lid. 4. 8M2743 Gauge. 5. Pressure tap fitting. 6. 1P7443 Tachometer. 7. 4S6997 Manifold Pressure Gauge.

Gas Line Pressure

Gas engines burn a wide range of gaseous fuels. BTU rating of a fuel is a measure of the power content of the fuel. The higher BTU rated fuels need less gas pressure to have the correct gas volume for a specific horsepower.

The BTU HHV (high heat value) of gaseous fuels. is the unit of measurement of the total fuel heat content. The BTU LHV (low heat value) content is more important. The combustion procedure in a cylinder causes carbon dioxide and water, but the heat needed for the conversion of water into vapor is lost and cannot be used in the engine. The remainder of the heat that can be used from the fuel is the LHV, and, as a rule, is 10% less than the HHV of natural gas. When BTU HHV is given, remember to make a conversion to LHV so the correct settings can be made.

Low octane fuels burn so fast that an adjustment to the timing must be made to move it back (retard). With early timing and low octane fuel, the fast burning fuel burns too much before the piston goes over top center. The result of this is "knocking" (detonation).

A change to the fuel to air ratio is made by changing the gas pressure in relation to the air pressure. Too much gas makes a "rich mixture" and not enough gas makes a "lean mixture". Either will cause a loss of power. If the compression is too high and the fuel to air mixture is too rich, fuel ignition will be without the aid of the spark and at a time different than the timing setting. When Propane gas is used, the adjustment of the fuel to air setting must be made with much more precision than when natural gas is used.

Make an adjustment to (regulate) the pressure in main gas supply to the engine. Naturally aspirated engines need main gas supply line pressure of 3 to 20 psi (20 to 140 kPa). Turbocharged engines need more pressure, 12 to 20 psi (85 to 140 kPa); 20 psi (140 kPa) is the maximum pressure that can be used in this engine. If the main line pressure of the gas supply is more than 20 psi (140 kPa), another regulator is needed.

Adjustment To Gas Pressure Regulator

4S6553 Instrument Group.

Before the engine can be started an adjustment to the gas pressure regulator must be made either when the engine is installed, when work is done on the regulator or when there is a change in the BTU content of the fuel. Adjustments can be made with either the 4S6553 Instrument Group or a water manometer.

PLUG REMOVAL
1. Plug on gas inlet line. 2. Plug on air inlet.

1. Remove plugs (1) and (2).

2. Turn the power mixture screw (6) adjustment to center between "R" (rich) and "L" (lean) position.

3. Connect one end of the manometer or one side of a differential gauge of the 4S6553 Instrument Group to the gas supply connection at (5) at the carburetor. Connect the other end of the manometer or other side of the differential gauge to the air inlet at (7). On engines with a balance line, connect the second end of the manometer or second side of the differential gauge either to a tee (4) installed at the balance line connection or to the balance line connection at the air inlet at (7) on the carburetor.

4. Open valve (10) if a manometer is used.

NOTE: If a manometer is used, the valve (10) must be closed while the engine is being stopped or started. This will prevent the manometer fluid from getting into the inlet of the carburetor (5).

CHECKING THE GAS PRESSURE REGULATOR ADJUSTMENT
A. Positive pressure differential. 3. Adjustment screw. 4. Tee and manometer connection. 5. Gas supply connection at carburetor. 6. Power mixture adjustment. 7. Air inlet connection at carburetor. 8. Gas pressure regulator. 9. Manometer or 4S6553 Instrument Group. 10. Valve.

5. Open the main gas valve and make an adjustment to the gas pressure regulator to cause a differential reading of 5.5 in. (139.7 mm) of water. The regulator adjustment is made by removing the cap on the top of the regulator and turning the screw (3) clockwise to cause an increase in the output pressure, and counterclockwise to cause a decrease in the pressure.

6. Start the engine and make adjustments to the fuel to air ratio.

Adjustment To The Fuel To Air Ratio

For Engines With Loads Which Go Up With an Increase of the Engine Speed (Examples: Turbine Pumps, Fans)

1. See the subject Adjustment to the Gas Pressure Regulator for the correct procedure to get the engine started.

2. Install an accurate tachometer on the engine.

3. Remove the plug on the regulator so adjustment screw can be turned.

NOTE: On turbocharged engines, a special tool is necessary to prevent the turbocharger boost from leaking and giving a wrong reading on the gauge or manometer.

4. Start and run the engine with a constant load at an rpm that is more than 3/4 the Full Load Setting. See the FUEL SETTING INFORMATION.

5. Hold (clamp) the throttle lever in place so it will not move.

6. Remove the governor linkage from the throttle lever.

7. Change the gas pressure by making an adjustment to the adjustment screw to get maximum rpm.

8. After getting maximum rpm, make a 3% reduction in the value of this rpm by making an adjustment with the screw to remove some of the force of the regulator spring. This will make the fuel to air ratio more "lean" until the desired rpm is found. This is the correct fuel to air ratio setting.

9. Connect the governor linkage and remove the restriction on the throttle lever.

For Engines Driving Loads at a Constant Speed and Constant Output (Examples: Electric Sets, Piston Compressors)

1. See the subject Adjustment to the Gas Pressure Regulator for the correct procedure to get the engine started.

2. Remove plug (2) from the inlet manifold.

3. Install a pressure gauge to the hole in the inlet manifold to give a reading of the inlet manifold pressure.

4. Install an accurate tachometer on the engine.

5. Start the engine and put a constant load on the engine. Run the engine at a speed between 1/2 and 3/4 of the Full Load rpm. See the FUEL SETTING INFORMATION. Permit the governor to keep the engine at a constant rpm.

CHECKING INLET MANIFOLD PRESSURE
1. Power mixture screw. 2. Plug in inlet manifold.

6. Make an adjustment to the spring compression in the regulator with the adjustment screw until the minimum pressure of the inlet manifold is found.

NOTE: On turbocharged engines a special tool is necessary to prevent the turbocharger boost from leaking and not putting the correct pressure on the top of the regulator diaphragm.

7. When the minimum inlet manifold pressure is found, make a decrease in the force of the spring on the diaphragm until there is an increase of 1 inch of mercury (25.4 mm of mercury) of the inlet manifold pressure. This is the correct fuel to air ratio setting.

NOTE: Be sure that the engine rpm is constant while the adjustments are being made. Any sudden change in rpm will make the adjustments wrong.

Adjustment of the Power Mixture Screw

Normally the power mixture screw (1) setting is at the center position between "L" (lean) and "R" (rich) (2 1/2 spaces from the full lean position). A small adjustment of the power mixture screw (1) will cause a large change to the fuel to air ratio of the engine. The power mixture screw must not be moved after the adjustment has been made to the line pressure regulator.

However, if the adjustment screw in the regulator is such that a minimum compression is on the spring and the fuel and air mixture is still too "rich", turn the power mixture screw 1/8 to 1/4 space at a time toward the "L" (lean) to "lean" out the mixture. Each time the power mixture screw is moved an adjustment to the line pressure regulator must be made to get the correct balance point between the power mixture screw and the regulator.

POWER MIXTURE SCREW
1. Power mixture screw. 2. Plug in inlet manifold.

Adjustment To The Thermac Propane System

4S6553 Instrument Group.

1. Connect one end of the water manometer (9) or one side of a differential gauge of the 4S6553 Instrument Group to the gas supply at (5) at the carburetor. Connect the other end of the manometer or other side of the differential gauge to the air inlet. On engines with a balance line connect the second end of the manometer or second side of the differential gauge to a tee installed either at the balance line connection on the vacuum regulator at (11) or to the balance line connection on the air inlet of the carburetor.

2. Open the main propane supply valve.

3. Make adjustment to the gas pressure regulator (6) to get a differential reading of 10 in. (254.0 mm) of water. The Thermac valve (2) will give a reduction to -1 in. (-25.4 mm) of water.

4. Start engine and make adjustment to the load adjusting valve (7) to get -2 in. (-50.8 mm) of water pressure differential (A) at full load.

5. Make adjustment to power mixture adjustment on the carburetor to 1/2 space to the "L" (lean) side of the center mark.

PROPANE GAS REGULATOR COMPONENTS (THERMAC SYSTEM)
A. Negative pressure differential. 1. Balance line. 2. Thermac valve. 3. Inlet air. 4. Carburetor. 5. Gas supply at carburetor. 6. Gas pressure regulator. 7. Load adjusting valve. 8. Air fuel mixture. 9. Manometer or 4S6553 Instrument Group. 10. Valve. 11. Tee and manometer connection. 12. Propane gas supply.

Adjustment To Vacuum Regulator (On Engines with Propane Gas)

4S6553 Instrument Group.

1. Remove plugs (1) and (2) from the carburetor.

PLUG REMOVAL
1. Plug on gas inlet line. 2. Plug on the air inlet.

2. Connect one end of the water manometer or one side of a differential gauge of the 4S6553 Instrument Group to the gas supply connection at the carburetor (3). Connect the other end of the manometer or other side of the differential gauge to the air inlet. On engines with a balance line connect the second end of the manometer or second side of the differential gauge to a tee (2) installed at the balance line connection on the vacuum regulator or to the balance line connection on the air inlet of the carburetor.

CHECKING THE VACUUM REGULATOR ADJUSTMENT
B. Negative pressure differential. 1. Adjustment nut. 2. Tee and manometer connection. 3. Propane supply connection at carburetor. 4. Power mixture adjustment. 5. Air inlet connection at carburetor. 6. Vacuum regulator. 7. Manometer or 4S6553 Instrument Group. 8. Valve.

NOTE: If a manometer is used, valve (8) must be closed while the engine is being stopped or started. This will prevent the manometer fluid from getting into the inlet of the carburetor.

3. Open the main propane supply valve. Start the engine and open valve (8). Make adjustment to the vacuum regulator to get the measurement (B) to -1 in. (-25.4 mm) of water at idle speed.

4. Make adjustment to the power mixture adjustment (4) to 1/2 space to the "L" (lean) side of the center mark.

Adjustments To The Dual Fuel System

Engines Using Natural Gas and Propane

Adjustments to the dual fuel system components must be made one at a time. Make an adjustment to the gas pressure regulator (6). See the subject ADJUSTMENT TO THE FUEL TO AIR RATIO. Be sure the adjustment procedure used is for the correct load application.

Make an adjustment to the vacuum regulator (9). Make reference to the subject ADJUSTMENT TO THE VACUUM REGULATOR. Make a setting of the load adjusting valve (5) to the mark in the center between "L" (lean) and "R" (rich).

DUAL FUEL SYSTEM (NATURAL GAS AND PROPANE)
1. Gas supply at carburetor. 2. Carburetor. 3. Power mixture adjustment. 4. Air inlet. 5. Load adjusting valve. 6. Gas pressure regulator. 7. Natural gas supply. 8. Propane supply. 9. Vacuum regulator.

Engines Using Digester Gas and Natural Gas

If digester gas is used with natural gas in a dual fuel system a digester gas carburetor (2) must be used. The natural gas supply (8) is controlled by the vacuum regulator (9) and the digester gas supply is controlled by the gas pressure regulator (6).

1. Open the main supply valve for the digester gas.

2. Make adjustments to the gas pressure regulator (6) as given in the earlier subject ADJUSTMENTS TO THE FUEL TO AIR RATIO. Be sure to use the correct procedure for the load application of the engine.

3. Close the main supply valve for the digester gas and open the main supply valve for the natural gas.

4. Make a setting of the load adjusting valve (5) to one mark to the "L" (lean) side of center.

5. Make adjustments to the vacuum regulator (9) as given in the subject ADJUSTMENT TO THE FUEL TO AIR RATIO.

NOTE: When digester gas and natural gas are used in a dual fuel system the vacuum regulator adjustments are made using the same procedure as the adjustments for the gas pressure regulator. Be sure to use the correct procedure for the load application of the engine.

DUAL FUEL SYSTEM (NATURAL GAS AND DIGESTER GAS)
1. Gas supply at carburetor. 2. Digester carburetor. 3. Power mixture adjustment. 4. Air inlet. 5. Load adjusting valve. 6. Gas pressure regulator. 7. Digester gas supply. 8. Natural gas supply. 9. Vacuum regulator.

How To Find Gas Leaks

Combustion gases leaking from natural gas engines can be a danger to safety. To find gas leaks, use the 1P1830 Explosimeter Group. It is made up of the explosimeter instrument (1) a five foot sampling line (2) and several replacement parts which are in a carrying case.

After there has been work on the fuel system, use the explosimeter to check connections and any other place gas leaks can be.

1P1830 EXPLOSIMETER
1. Explosimeter. 2. Sampling line.

The concentration of flamable gases is shown in percent explosive by the indicator.

Detailed operating and maintenance instructions are with the group.

Exhaust Temperature

Use the 1P3060 Pyrometer Group to check the exhaust temperature. Take temperature readings soon after the engine is installed. Regular checks are needed, and a record kept, to find any large increase or decrease in exhaust temperature.

Exhaust temperatures will not be the same for all engines of a similar type. Factors that have an affect on the exhaust temperatures are:

1. Restriction in the air inlet system

2. Restriction in the exhaust system

3. Temperature of the inlet air

4. Friction inside the engine

5. Fuel rate, fuel system condition or setting

6. Height of engine above sea level (altitude)

7. Size of valve openings

8. Condition of pyrometer thermocouple

9. Location of thermocouple

Checking the exhaust temperature, by itself, is not a complete method of making an analysis of an engine problem. A large or sudden temperature change will give an indication that something is wrong in the engine. Other checks must be made to find the cause. Special Instruction Form No. SMHS7179 is with the tool group and gives instructions for the test procedure.

1P3060 PYROMETER GROUP

Cylinder Head

Spark Plug Adapters

Use a 8S7227 Wrench and 8H8538 Socket to remove and install the spark plug adapters. Put liquid soap on the bore in head and seal. Put 5P3931 Anti-Seize Compound on the threads.

Valves

The illustration shows the 5S1330 Valve Spring Compressor Assembly with 5S1329 Jaw (1) to put the valve spring under compression. The 5S1322 Valve Keeper Installer (2) used with the compressor assembly makes installation of the valve keepers easier and faster.

COMPRESSION OF VALVE SPRINGS (Typical Illustration)
1. 5S1329 Jaw. 2. 5S1322 Valve keeper installer.

The valves can also be removed with 7F4992 Valve Spring Compressor Group. The 7F4290 Adapter is installed or a rocker arm stud. When installing the valve springs with 7F4292 Group, use the FT196 Fabricated tool to hold the valves in place.

Valve Clearance

NOTE: Valve clearance is measured between the rocker arm and the valves.

NOTE: When the valve lash (clearance) is checked, adjustment is NOT NECESSARY if the measurement is in the range given in the chart for VALVE CLEARANCE CHECK: ENGINE STOPPED. If the measurement is outside this range, adjustment is necessary. See the chart for VALVE CLEARANCE SETTING: ENGINE STOPPED, and make the setting to the normal (desired) specifications in this chart.

VALVE CLEARANCE ADJUSTMENT
1. Adjustment screw. 2. Locknut. X. Valve clearance.

1. Put No. 1 piston at top center (TC) on the compression stroke. Make reference to FINDING TOP CENTER COMPRESSION POSITION FOR NO. 1 PISTON.

2. Make an adjustment to the valve clearance on the intake valves for cylinders 1, 2, and 4. Make an adjustment to the valve clearance on the exhaust valves for cylinders 1, 3 and 5.

3. Turn the flywheel 360° in the direction of engine rotation. This will put No. 6 piston at top center (TC) on the compression stroke.

4. Make an adjustment to the valve clearance on the intake valve for cylinders 3, 5, and 6. Make an adjustment to the valve clearance on the exhaust valves for cylinders 2, 4, and 6.

5. After valve adjustment is correct, tighten the nuts for the valve adjustment screws to 40 ± 5 lb. ft. (55 ± 7 N·m).

CYLINDER AND VALVE LOCATION

Procedure For Measuring Camshaft Lobes

To find lobe lift (A) of camshaft, use the procedure that follows:

A. Measure camshaft lobe height (B).

B. Measure base circle (C).

C. Subtract base circle (STEP B) from lobe height (STEP A). The difference is actual lobe lift (A).

D. Specified camshaft lobe lift (A) is .4030 in. (10.236 mm).

Maximum permissible difference between actual lobe lift (STEP C) and specified lobe lift (STEP D) is .010 in. (0.25 mm).

CAMSHAFT LOBE
A. Lobe lift. B. Lobe height. C. Base circle.

Valve Seat Inserts

Valve seat inserts are available with a larger outside diameter than the original size. The available inserts are in the chart.

Valve Guides

Install valve guides so the top of the guide is above the surface of the head 1.690 ± 0.020 in. (42.93 ± 0.51 mm). Use the 4H446 Driver Assembly and the 5P1727 Bushing to install the guides to the correct height. Be sure the small diameter of the guide is at the top of the bushing when installing the guides.

Water Directors

There are twelve water directors (1) installed in each cylinder head. They give the coolant the desired direction of flow. On the exhaust side, the coolant flow goes toward the precombustion chambers and the exhaust valve ports; and on the intake side, the coolant flow goes to the other side of the valve ports.

WATER DIRECTORS
1. Water director. 2. Seal. 3. Ferrule.

Water directors are installed with a press in the heads after the alignment of the notch on the director with the V-mark on the head.

FT117 SEAL AND FERRULE ASSEMBLY TOOL

4. 5H3182 Pin.

5. 2A3672 Spring.

6. Flat Washer.

7. Chain

8. Upper Rod.

9. Connecting Pin.

10. Bracket.

11. Connecting Joint.

12. Lower Rod.

13. Base.

A. Rubber Seals.

B. Ferrule.

Replacement type seals (2) and ferrule (3) go between the head and top of the block. Put soap on the inner surface of the seal and put the seal over the flange on the ferrule before installing. Use the FT117 Seal and Ferrule Assembly Tool to install the seal on the ferrule

Differential Pressure Regulator

The regulator has two .25 in. (6.4 mm) spacers (3) for altitude adjustment. Both spacers must be used for operation up to 1500 feet (457 m) altitude. Remove one for operating between 1500 and 4000 feet (457 and 1219 m). All spacers can be removed for operating between 4000 and 6500 feet (1219 and 1981 m). Make a small adjustment by adding or removing shims (9). The bolts of the regulator assembly must be sealed.

To test the regulator with both spacers (3) in place, and atmospheric pressure in spring compartment, use a pressure of 6.66 to 7.21 psi (46.1 to 50.0 kPa) in the chamber, through connection (2). Measurement at (1) must be 2.893 in. (73.5 mm). Special Instruction Form No. FE034610 shows the equipment for testing and adjusting this regulator. Use large enough lines to supply the volume of air needed. Use a Tee in the line to connect the gauge. The Tee must be installed so the gauge is at the opposite end of the Tee from the connection to the regulator. The supply pressure will be attached to the third side of the Tee.

REGULATOR
1. Measurements for testing regulator. 2. Pressure sensing port connection. 3. Spacers. 4. Bypass valve. 5. Breather location. 6. Bypass passage. 7. Exhaust regulator bypass housing. 8. Diaphragm. 9. Shims.

Governor Adjustments

High Idle RPM

The engine idle rpm can be checked at the connection for the tachometer drive on the service meter after the cover has been removed. The rpm will be one half of engine rpm.

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NOTICE
A mechanic with training in governor adjustments is the only one to make the adjustment to the high idle and low idle rpm. The correct high idle and low idle rpm is in the FUEL SETTING INFORMATION.

CHECKING ENGINE RPM

To make an adjustment to the high idle rpm use the following procedure:

1. Remove cover (2) from the top of the housing for the governor.

2. Turn adjustment screw (3) as necessary to change high idle rpm.

LOCATION OF ADJUSTMENTS
1. Retainer hole in cover. 2. Cover. 3. Adjustment screw for high idle.

3. After an idle adjustment is made, move the governor lever to change the rpm of the engine.

4. Now move the governor lever back to the point of first adjustment. Use this procedure until the idle rpm is the same as the idle rpm given in the FUEL SETTING INFORMATION.

NOTE: Turning the adjustment screw counterclockwise will cause the rpm to have an increase. Turning the adjustment screw clockwise will cause the rpm to have a decrease.

5. When governor adjustment is correct, put the cover on the governor. Then put the cover on the service meter.

Low Idle RPM

The adjustment to the low idle rpm is made with the screw on the throttle shaft lever. See the subject CARBURETOR for the correct adjustment procedures.

Adjustment of Linkage to the Carburetor

Three basic uses of the 1P2385 Protractor tools are shown here.

1P2385 PROTRACTOR TOOL USE
A. Indicator used for angle setting. B. Protractor plate edge in alignment with lever. C. Vertical housing face and extension arm are in alignment. D. Bubble in level. E. Indicator used for angle setting. F. Extension arm in alignment with lever. G. Extension arm in alignment with lever. H. Plate edge in alignment with second lever. I. Indicator used for angle setting. J. Angle between lever and vertical face of housing. K. Angle between level and lever. L. Angle between levers.

1. Put governor lever (4) in fuel off position.

2. Turn control shaft (2) so that the throttle plate is in the closed position. This is low idle.

3. Install lever (1) on control shaft (2) so the angle from vertical is 42°.

4. Make an adjustment to the rod (3) so it is the correct length when installed on levers (1 and 4). Install the end on lever (1) so it is in the hole 1 in. (25.4 mm) from the center of the control shaft (2).

ADJUSTMENT OF LINKAGE TO THE CARBURETOR
1. Lever on carburetor control shaft. 2. Carburetor control shaft. 3. Rod. 4. Governor control lever.

Lubrication System

One of the problems in the following list will generally be an indication of a problem in the lubrication system for the engine.

TOO MUCH OIL CONSUMPTION

OIL PRESSURE IS LOW

OIL PRESSURE IS HIGH

TOO MUCH COMPONENT WEAR

Too Much Oil Consumption

Oil Leakage on Outside of Engine

Check for leakage at the seals at each end of the crankshaft. Look for leakage at the oil pan gasket and all lubrication system connections. Check to see if oil is coming out of the crankcase breather. This can be caused by combustion gas leakage around the pistons. A dirty crankcase breather will cause high pressure in the crankcase, and this will cause gasket and seal leakage.

Oil Leakage Into Combustion Area of Cylinders

Oil leakage into the combustion area of the cylinders can be the cause of blue smoke. There are four possible ways for oil leakage into the combustion area of the cylinders:

1. Oil leakage between worn valve guides and valve stems.

2. Worn or damaged piston rings or dirty oil return holes.

3. There can be a leakage of oil past the ring seals at the impeller end of the turbocharger shaft.

4. Compression ring not installed correctly.

Too much oil consumption can also be the result of using oil with the wrong viscosity Oil with a thin (low) viscosity can be caused from fuel getting in the crankcase, or by the engine getting too hot.

Oil Pressure Is Low

An oil pressure gauge that has a defect may give an indication of low oil pressure.

When the engine is running at full load rpm with SAE 10 oil, temperature at 200 ± 10°F (93 ± 6° C), the oil pressure measured at the clean side of the oil filter at the oil filter base will be 43 ± 7 psi (295 ± 50 kPa).

A lower pressure reading, 18 ± 7 psi (125 ± 50 kPa), is normal at low idling speeds. An 8M2744 Gauge, which is part of 7S8875 Hydraulic Test Box, can be used for checking pressure in the system.

7S8875 HYDRAULIC TEST BOX

Crankcase Oil Level

Check the level of the oil in the crankcase. Add oil if needed. It is possible for the oil level to be too far below the oil pump supply tube. This will result in the oil pump not having the ability to supply enough lubrication to the engine components.

Oil Pump Does Not Work Correctly

The inlet screen of the supply tube for the oil pump can have a restriction. The result will be cavitation and a loss of oil pressure. Air leakage in the supply side of the oil pump will also cause air in the oil (cavitation) and loss of oil pressure. If the pressure regulating valve for the system is held in the open (unseated) position, the lubrication system can not get to maximum pressure. Oil pump gears that have too much wear will cause a reduction in oil pressure.

Oil Filter and Oil Cooler Bypass Valve

If the bypass valve for the oil filter is held in the open position (unseated) and the oil filter has a restriction, a reduction in oil pressure will be the result.

The bypass valve is in the oil filter base. The bypass valve will cause the flow of oil to go around the filter elements when there is a reduction to the flow through the elements.

If the oil cooler has a restriction, the oil cooler bypass valve in the oil filter base will open. This will cause the flow of oil to go around the oil cooler.

Too Much Clearance at Engine Bearings or Open, Broken or Disconnected Oil Line or Passage in Lubrication System

Components that are worn and have too much bearing clearance can cause oil pressure to be low. Low oil pressure can also be caused by an oil line or oil passage that is open, broken, or disconnected.

Oil Cooler

Look for a restriction in the oil passage of the oil cooler.

If the oil cooler has a restriction the oil temperature will be higher than normal when the engine is running. The oil pressure of the engine will become low if the oil cooler has a restriction.

Oil Pressure Is High

Oil pressure will be high if the bypass valve for the oil pump can not move from the closed position.

Too Much Component Wear

When some components of the engine show bearing wear in a short time, the cause can be a restriction in an oil passage. A broken oil passage can also be the cause.

If the gauge for oil pressure shows the correct oil pressure, but a component is worn because it is not getting enough lubrication, look at the passage for oil supply to that component. A restriction in a supply passage will not let enough lubrication get to a component and this will cause early wear.

Turbocharger Component Wear

When the gauge for oil pressure shows the correct oil pressure and bearing failure or wear is present in the turbocharger, check the operation of the turbocharger lubrication valve. The valve can be in the open position and permit oil that is not clean to give lubrication to the turbocharger.

Cooling System

The engine has a pressure type cooling system. A pressure type cooling system gives two advantages. The first advantage is that the cooling system can operate safely at a temperature that is higher than the normal point where water changes to steam. The second advantage is that this type system prevents cavitation (air in inlet of pump) in the water pump. With this type system it is more difficult for an air or steam pocket to form in the cooling system.

The cause for an engine getting too hot is generally because regular inspections of the cooling system were not done. Make a visual inspection of the cooling system before testing with testing equipment.

Visual Inspection Of The Cooling System

1. Check coolant level in the cooling system.

2. Look for leaks in the system.

3. Look for bent radiator fins. Be sure that air flow through the radiator does not have a restriction.

4. Inspect the drive for the fan.

5. Check for damage to the fan blades.

6. Look for air or combustion gas in the cooling system.

7. Inspect the pressure cap and the sealing surface for the cap. The sealing surface must be clean.

8. Look for large amounts of dirt in the radiator core and on the engine.

Testing The Cooling System

Remember that temperature and pressure work together. When making a diagnosis of a cooling system problem, temperature and pressure must both be checked. Cooling system pressure will have an effect on cooling system temperatures. For an example, look at the chart to see the effect of pressure and the height above sea level on the boiling point (steam) of water.

Checking Coolant Temperatures

9S9102 Thermistor Thermometer Group.

The 9S9102 Thermistor Thermometer Group is used in the diagnosis of overheating (engine running too hot) or overcooling (engine running too cool) problems. This group can be used to check the different parts of the cooling system. The complete testing procedure is in Special Instruction Form No. SMHS7140.

9S9102 THERMISTOR THERMOMETER GROUP

Checking Radiator Air Flow

9S7373 Air Meter Group.

The 9S7373 Air Meter Group is used to check the air flow through the radiator core. Overheating can be caused by installing the wrong fan guard, low fan speed, or a restriction in the radiator core (clogging). The meter will give aid in finding a restriction in the core. The testing procedure and the correct readings are in Special Instruction Form No. SMHS7063.

9S7373 AIR METER GROUP

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Make all checks at engine LOW IDLE and on the side of the radiator opposite the fan. Wear eye protection.

CHECKING AIR FLOW IN CROSS AND DIAGONAL LINES (Typical Illustration)

Take readings in a cross and diagonal pattern. Make a comparison of the readings in each line the same distance from the center of the fan. Permit differences for restrictions such as guards, braces and engine components which will cause a change in the rate of air flow.

NOTE: All readings are taken at engine LOW IDLE.

AIR FLOW (Typical Illustration)
1. Fan hub area. 2. Fan blade area. 3. Area outside fan blade.

If the readings are not within the ranges, stop the engine, put a strong light behind the core and inspect for a restriction. If the restriction is from dirt, remove by steam cleaning. If the restriction is from bent fins use 2H1822 Radiator Fin Comb to make the fins straight.

INSPECTING RADIATOR CORE FOR RESTRICTION (Typical Illustration)

Checking Fan Speed

6V3121 Multitach Group

The 6V3121 Multitach Group can measure fan speed by the use of the photo pickup and reflective tape. Special Instruction Form No. SEHS7807 has instructions for its use.

6V3121 MULTITACH GROUP

Pressure Cap

One cause for a pressure loss in the cooling system can be a bad seal on the pressure cap of the system. Inspect the pressure cap carefully. Look for damage to the seal or the sealing surface. Any foreign material or deposits on the cap, seal or sealing surface must be removed.

To check the pressure cap for the pressure that makes the pressure cap open, use the following procedure:

1. Remove the pressure cap from the radiator.

SCHEMATIC OF PRESSURE CAP
A. Sealing surface of cap and radiator.

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Always stop the engine to inspect the cooling system. Loosen the pressure cap to the first stop and let the pressure out of the cooling system, then remove the pressure cap. Hot coolant and steam can cause personal injury. Let coolant become cool before it is drained.

2. Put the pressure cap on the 9S8140 Cooling System Pressurizing Pump Group.

3. Look at the gauge for the exact pressure that makes the pressure cap open.

9S8140 COOLING SYSTEM PRESSURIZING PUMP GROUP

4. Make a comparison of the reading on the gauge with the correct pressure at which the pressure cap must open.

NOTE: The correct pressure that makes the pressure cap open is on the pressure cap and is also in the SPECIFICATIONS.

5. If the pressure cap is bad, install a new pressure cap.

Testing Radiator and Cooling System for Leaks (Systems That Use Pressure Cap)

To test the radiator and cooling system for leaks, use the procedure that follows:

1. Remove the pressure cap from the radiator.

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Always stop the engine to inspect the cooling system. Loosen the pressure cap to the first stop and let the pressure out of the cooling system, then remove the pressure cap. Hot coolant and steam can cause personal injury. Let coolant become cool before it is drained.

2. Make sure the coolant is over the top of the radiator core.

3. Put the 9S8140 Cooling System Pressurizing Pump Group on the radiator.

4. Get the pressure reading on the gauge to 3 psi (20 kPa) more than the pressure on the pressure cap.

5. Check the radiator for outside leakage.

6. Check all connections and hoses for the cooling system for outside leakage.

7. If you do not see any outside leakage and the pressure reading on the gauge is still the same after 5 minutes, the radiator and cooling system does not have leakage. If the reading on the gauge goes down and you do not see any outside leakage, there is leakage on the inside of the cooling system. Make repairs as necessary.

Water Temperature Regulators

1. Remove the regulator from the engine.

2. Heat water in a pan until the temperature is correct for opening the regulator according to the chart. Move the water around in pan to make it all be the same temperature.

3. Hang the regulator in the pan of water. The regulator must be below the surface of the water and it must be away from the sides and bottom of the pan.

4. Keep the water at the correct temperature for 10 minutes.

5. Remove the regulator from the water. Immediately make a measurement of the distance the regulator is open.

6. If the regulator is open to a distance less than given in the chart, install a new regulator.

NOTE: When installing a regulator inspect seal for defects and change if necessary.

9S9102 Thermistor Thermometer Group

The 9S9102 Thermistor Thermometer Group is used in the diagnosis of overheating (engine running too hot) or overcooling (engine running too cool) problems. This group can be used to check the different parts of the cooling system. The complete testing procedure is in Special Instruction Form No. SMHS7140.

9S9102 THERMISTOR THERMOMETER GROUP

PROBE FOR CHECKING

The probe must be installed in the coolant of the system being tested.

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NOTICE
Do not tighten the probe more than 30 lb. ft. (40 N·m) torque.

Check temperatures in the locations listed in the chart. Look at the chart to see if these comparisons are within the range in the chart. Make the needed checks if the temperatures are not within the ranges.

V-Belt Tension Chart

Basic Block

Connecting Rods And Pistons

Use the 7B7974 Piston Ring Expander to remove or install piston rings.

Use the 5P3527 Piston Ring Compressor to install pistons into cylinder block.

Tighten the connecting rod bolts in the following step sequence:

1. Put 2P2506 Thread Lubricant on threads and nut seat.

2. Tighten both nuts 75 ± 5 lb. ft. (100 ± 7 N·m)

3. Put a mark on each nut and cap.

4. Tighten each nut 60° from the mark.

The connecting rod bearings should fit tightly in the bore in the rod. If bearing joints or backs are worn (fretted), check for bore size as this is an indication of wear because of looseness.

Connecting Rod And Main Bearings

Bearings are available with .025 in. (0.64 mm) and .050 in. (1.27 mm) small inside diameter than the original size bearings. These bearings are for crankshafts that have been "ground" (made smaller than the original size).

Piston Ring Groove Gauge

Pistons With Straight Sides in Ring Grooves

A 5P3519 Piston Ring Groove Gauge is available for checking ring grooves with straight sides. For instructions on the use of the gauge, see the GUIDELINE FOR REUSABLE PARTS; PISTONS AND CYLINDER LINERS, Form No. SEBF8001.

5P3519 PISTON RING GROOVE GAUGE

Cylinder Liner Projection

For Engines With Spacer Plates

1P2397 Adapter Plate.8B7548 Push-Puller Crossbar and three3H465 Plates.7/8"-9 NC Bolts, 3 in. (76.2 mm) long.7/8"-9 NC Bolts, 7 in. (177.8 mm) long.7M7875 Head Bolt Washers.8S3140 Cylinder Block CounterboringTool Arrangement.1P5510 Liner Projection Tool Group.

Check liner projection above spacer plate (4) as follows:

1. Make certain that spacer plate (4) and the cylinder liner flange are clean.

2. Install the gasket and spacer plate (4) on the cylinder block. Use 7/8 in.-9 NC bolts, 3 in. (76.2 mm) long, with two 7M7875 Washers (3) on each bolt to secure spacer plate (4) to the cylinder block. Place two bolts with washers on each side of the cylinder liner. Tighten the bolts evenly, in four steps; 10 lb. ft. (14 N·m), 25 lb. ft. (35 N·m), 50 lb. ft. (70 N·m) and finally to 70 lb. ft. (95 N·m).

NOTE: To avoid moving bolts and washers as each liner is checked, install two bolts with washers on each side of each cylinder liner, along the entire length of the spacer plate.

SECURING SPACER PLATE TO CYLINDER BLOCK (Typical Example)
1. 3H465 Plate. 2. 1P2397 Adapter Plate. 3. Cylinder head bolt washers. 4. Spacer plate.

3. Invert 3H465 Plate (1) from an 8B7548 Push Puller, in the center of adapter plate (2). Center crossbar (6) on the inverted 3H465 Plate. Using two 7/8 in.-9 NC bolts 7 in. (177.8 mm) long and two 3H465 Plates, secure the crossbar to the cylinder block as illustrated. Tighten the bolts evenly, in four steps; 5 lb. ft. (7 N·m), 15 lb. ft. (20 N·m), 25 lb. ft. (35 N·m) and finally to 50 lb. ft. (70 N·m). Distance from bottom edge of crossbar to top plate, must be the same on both sides of cylinder liner.

4. Zero the dial indicator using the back of 1P5507 Gauge with dial indicator (5) mounted in 1P2402 Gauge Body (7).

5. Measure liner projection as close as possible to the clamping area and at four locations around the liner. The liner projection must be within .005 ± .003 in. (0.13 ± 0.08 mm) and the four measurements should not vary more than .002 in. (0.05 mm). The average projection between adjacent cylinders for the same cylinder head must not vary more than .002 in. (0.05 mm).

MEASURING LINER HEIGHT PROJECTION (Typical Example)
5. Dial Indicator. 6. Crossbar. 7. 1P2402 Gauge Body.

NOTE: If liner projection varies from point to point around the liner, rotate the liner to a new position within the bore. If still not within specified limits move liner to a different bore.

NOTE: Measure and check the following dimensions when installing new parts. With all dimensions correct, proceed with the listed Steps.

a. Spacer plate thickness, .486 ± .001 in. (12.34 ± 0.03 mm).

b. Spacer plate gasket thickness, .008 ± .001 in. (0.20 ± 0.03 mm). (All surfaces must be clean and dry when installing gasket).

c. Cylinder liner flange thickness, .4990 ± .0008 in. (12.675 ± 0.020 mm).

Liner projection can be adjusted by machining the contact face of the cylinder block with use of the 8S3140 Cylinder Block Counterboring Tool Arrangement. Form FM055228 is part of the cylinder block counterboring tool arrangement and gives tool arrangement and tool usage information.

The counterboring depth ranges from a minimum of .030 in. (0.76 mm) to a maximum of .045 in. (1.14 mm). Put a .030 in. (0.76 mm) shim directly beneath the liner flange. If more than one shim is installed put the other shims under the .030 in. (0.76 mm) shim.

Shims of various thicknesses also are available to adjust liner projection.

Cylinder Liner Projection For Engines Without Spacer Plates

1P2397 Puller Plate.8B7548 Push Puller Crossbar and three3H465 Plates.8S3140 Cylinder Block CounterboringTool Arrangement.1P5510 Liner Projection Tool Group.

1. Make sure that the bore in block and the cylinder liner flange are clean.

2. Use a 1P2397 Puller Plate (5), three 3H465 Plates (1) and the crossbar (4) from the 8B7548 Push Puller, to hold the liner down with stud nuts for the cylinder head.

3. Tighten the nuts to 50 lb. ft. (70 N·m). Tighten the nuts evenly in four steps; 5 lb. ft. (7 N·m), 15 lb. ft. (20 N·m), 25 lb. ft. (35 N·m), then to 50 lb. ft. (70 N·m). The distance from bottom edge of the crossbar, to the cylinder block must be the same on both sides of the cylinder liner.

4. Use a 1P5510 Liner Projection Tool Group as illustrated, to measure liner projection. Special Instruction Form No. SMHS7727 is with the tool. Liner projection must be .004 to .008 in. (0.10 to 0.20 mm). The maximum difference in height of liners next to each other under the same cylinder head is .002 in. (0.05 mm). The maximum difference between high and low measurements made at four places around each cylinder is .002 in. (0.05 mm). Shims are available for adjustment of the liner projection.

MEASURING LINER PROJECTION
1. 3H465 Plate. 2. Dial Indicator. 3. 1P2402 Gauge Body. 4. Crossbar. 5. 1P2397 Puller Plate.

5. Use the 8S3140 Counterboring Tool Arrangement to bore the block deeper if needed. Maximum depth of the bore is .538 in. (13.67 mm). Special Instruction Form No. FM055228 gives an explanation of the use of the 8S3140 Counterboring Tool Arrangement.

Cylinder Block

1P4000 Line Boring Tool Group.1P3537 Dial Bore Gauge Group.

The bore in the block for main bearings can be checked with main bearing caps installed without bearings. Tighten the nuts holding the caps to the torque shown in the SPECIFICATIONS. Alignment error in the bores must not be more than .003 in. (0.08 mm). Special Instruction Form No. SMHS7606 gives the use of 1P4000 Line Boring Tool Group to machine the main bearing bores. 1P3537 Dial Bore Gauge Group can be used to check the size of the bores. Special Instruction Form No. GMG00981 is with the group.

1P3537 DIAL BORE GAUGE GROUP

Vibration Damper

Damage to or failure of the damper will cause an increase in vibrations and can result in damage to the crankshaft.

VIBRATION DAMPER
1. Flywheel ring. 2. Rubber ring. 3. Inner hub. 4. Bolt.

The damper needs replacement when the holes for the bolts have wear and the fit between the bolts and the holes is loose.

Flywheel And Flywheel Housing

8S2328 Dial Indicator Group.

Flywheel Ring Gear

Heat the ring gear to a maximum of 600° F (316° C) to install. Install the ring gear so the chamfer on the gear teeth is next to the starter pinion when the flywheel is installed.

Face Runout (axial eccentricity) of the Flywheel Housing

If any method other than given here is used, always remember bearing clearances must be removed to get correct measurements.

1. Fasten a dial indicator to the crankshaft flange so the anvil of the indicator will touch the face of the flywheel housing.

8S2328 DIAL INDICATOR GROUP INSTALLED

CHECKING FACE RUNOUT OF THE FLYWHEEL HOUSING
A. Bottom. B. Right side. C. Top. D. Left side.

2. Force the crankshaft to the rear before reading the indication at each point.

3. With dial indicator set at .000 in. (0.0 mm) at location (A), turn the crankshaft and read the indicator at locations (B), (C) and (D).

4. The difference between lower and higher measurements taken at all four points must not be more than .012 in. (0.30 mm), which is the maximum permissible face runout (axial eccentricity) of the flywheel housing.

Bore Runout (radial eccentricity) of the Flywheel Housing

NOTE: Write the dial indicator measurements with their positive (+) and negative (-) notation (signs). This notation is necessary for making the calculations in the chart correctly.

1. With the dial indicator in position at (C), adjust the dial indicator to "0" (zero). Push the crankshaft up against the top bearing. Write the measurement for bearing clearance on line 1 in column (C).

CHECKING BORE RUNOUT OF THE FLYWHEEL HOUSING

8S2328 DIAL INDICATOR GROUP INSTALLED

2. Divide the measurement from Step 1 by 2. Write this number on line 1 in columns (B) & (D).

3. Turn the crankshaft to put the dial indicator at (A). Adjust the dial indicator to "0" (zero).

4. Turn the crankshaft counterclockwise to put the dial indicator at (B). Write the measurement in the chart.

5. Turn the crankshaft counterclockwise to put the dial indicator at (C). Write the measurement in the chart.

6. Turn the crankshaft counterclockwise to put the dial indicator at (D). Write the measurement in the chart.

7. Add lines I & II by columns.

8. Subtract the smaller number from the larger number in line III in columns (B) & (D). The result is the horizontal "eccentricity" (out of round). Line III, column (C) is the vertical eccentricity.

9. On the graph for total eccentricity find the point of intersection of the lines for vertical eccentricity and horizontal eccentricity.

GRAPH FOR TOTAL ECCENTRICITY

10. If the point of intersection is in the range marked "Acceptable," the bore is in alignment. If the point of intersection is in the range marked "Not Acceptable," the flywheel housing must be changed.

Face Runout (axial eccentricity) of the Flywheel

1. Install the dial indicator as shown. Force the crankshaft the same way before the indicator is read so the crankshaft end clearance (movement) is always removed.

2. Set the dial indicator to read .000 in. (0.0 mm).

3. Turn the flywheel and read the indicator every 90°.

4. The difference between the lower and higher measurements taken at all four points must not be more than .006 in. (0.15 mm), which is the maximum permissible face runout (axial eccentricity) of the flywheel.

CHECKING FACE RUNOUT OF THE FLYWHEEL

Bore Runout (radial eccentricity) of the Flywheel

1. Install the dial indicator (3) and make an adjustment of the universal attachment (4) so it makes contact as shown.

2. Set the dial indicator to read .000 in. (0.0 mm).

3. Turn the flywheel and read the indicator every 90°.

4. The difference between the lower and higher measurements taken at all four points must not be more than .006 in. (0.15 mm), which is the maximum permissible bore runout (radial eccentricity) of the flywheel.

5. Runout (eccentricity) of the bore for the pilot bearing for the flywheel clutch, must not exceed .005 in. (0.13 mm).

CHECKING FLYWHEEL CLUTCH PILOT BEARING BORE

CHECKING BORE RUNOUT OF THE FLYWHEEL
1. 7H1945 Holding Rod. 2. 7H1645 Holding Rod. 3. 7H1942 Indicator. 4. 7H1940 Universal Attachment.

Electrical System

Most of the tests of the electrical system can be done on the engine. The wiring insulation must be in good condition, the wire and cable connections must be clean and tight, and the battery must be fully charged. If the on the engine test shows a defect in a component, remove the component for more testing.

The service manual TESTING AND ADJUSTING ELECTRICAL COMPONENTS, Form No. REG00636 has complete specifications and procedures for the components of the starting circuit and the charging circuit.

Battery

5P300 Electrical Tester.9S1990 or 1P7400 Battery Charger Tester.5P957 or 5P3414 Coolant and Battery Tester.

NOTE: Make reference to Special Instruction Form No. SEHS7006 and to the instructions inside of the cover of the tester, when testing with the 5P300 Electrical Tester.

The battery circuit is an electrical load on the charging unit. The load is variable because of the condition of the charge in the battery. Damage to the charging unit will result, if the connections, either positive or negative) between the battery and charging unit are broken while the charging unit is charging. This is because the battery load is lost and there is an increase in charging voltage. High voltage will damage, not only the charging unit but also the regulator and other electrical components.

Show/hide table

Never disconnect any charging unit circuit or battery circuit cable from battery when the charging unit is operated. A spark can cause an explosion from the flammable vapor mixture of hydrogen and oxygen that is released from the electrolyte through the battery outlets. Injury to personnel can be the result.

Load test a battery that does not hold a charge when in use. To do this, put a resistance, across the main connections (terminals) of the battery. For a 6, 8 or 12 V battery, use a test load of three times the ampere/hour rating (the maximum test load on any battery is 500 amperes). Let the test load remove the charge (discharge) of the battery for 15 seconds and with the test load still applied test the battery voltage. A 6 V battery in good condition will show 4.5 V; an 8 V battery will show 6 V; a 12 V battery will show 9 V. Each cell of a battery in good condition must show 1.6 V on either a 6, 8 or 12 V battery.

Make reference to Special Instruction Form No. SEHS6891 when checking with the 9S1990 or 1P7400 Battery Charger Tester.

9S1990 BATTERY CHARGER TESTER

Charging System

5P300 Electrical Tester.

NOTE: Make reference to Special Instruction Form No. SEHS7006 and to the instructions inside of the cover of the tester, when testing with the 5P300 Electrical Tester.

The condition of charge in the battery at each regular inspection will show if the charging system is operating correctly. An adjustment is necessary when the battery is constantly in a low condition of charge or a large amount of water is needed (more than one ounce of water per cell per week or per every 50 service hours).

Make a test of the charging unit and voltage regulator on the engine, when possible, use wiring and components that are a permanent part of the system. Off the engine (bench) testing will give a test of the charging unit and voltage regulator operation. This testing will give an indication of needed repair. After tests are made, again make a test to give proof that the units are repaired to their original operating condition.

Before starting the on engine testing, the charging system and battery must be checked as given in the Steps below.

1. Battery must be at least 75% (1.240 Sp. Gr.) full charged and held tightly in place. The battery holder must not put too much stress on the battery.

2. Cables between the battery, starter and engine ground must be the correct size. Wires and cables must be free of corrosion and have cable supports clamps to prevent stress on battery connections (terminals).

3. Leads, junctions, switches and panel instruments that have direct relation to the charging circuit must give correct circuit control.

4. Inspect the drive components for the charging unit to be sure they are free of grease and oil and have the ability to operate the charging unit.

Delco-Remy Alternator; Pulley Nut Tightening

Tighten nut that holds the pulley to a torque of 75 ± 5 lb. ft. (100 ± 7 N·m) with the tools shown.

TOOLS TO TIGHTEN ALTERNATOR PULLEY NUT
1. 5P7425 Torque Wrench. 2. 8S1588 Adapter (1/2" female to 3/8" male drive). 3. FT1697 Socket. 4. 8H8517 Combination Wrench (11/8"). 5. FT1696 Wrench.

Alternator Regulator Adjustment

When an alternator is charging the battery too much or not enough, an adjustment can be made to the charging rate of the alternator.

Alternator Regulator (Delco-Remy)

ALTERNATOR REGULATOR ADJUSTMENT
1. Voltage adjustment cap.

To make an adjustment to the voltage output on these alternators, remove the voltage adjustment cap (1) from the alternator, turn the cap 90°, and install it again into the alternator. The voltage adjustment cap has four positions: HI, LO, and two positions between the high and the low setting.

ALTERNATOR REGULATOR (MOTOROLA)
1. Cap for adjustment screw.

When the alternator is either charging the battery too much or not enough, an adjustment can be made to the alternator charging rate. To make an adjustment to the voltage output, remove cap (1) from the alternator regulator and change the regulator adjustment with a screwdriver.

To increase the voltage turn the adjustment screw clockwise. The adjustment screw under the cap (1) has five positions (number 1 is the last position clockwise).

Generator

NOTE: Make reference to Special Instruction Form No. SEHS7006 and to the instructions inside of the cover of the tester, when testing with the 5P300 Electrical Tester.

When the generator is giving the battery too large or too small a charge, use a 5P300 Electrical Tester to check if the voltage regulator control, the current regulator control, or both need adjustment. To get a correct test the regulator cover must not be removed and the regulator must be at operating temperature.

The voltage regulator and current regulator controls have a spring tension adjustment screw. To cause an increase in generator voltage or current turn adjusting screw (1), to put more spring force on the correct control. Make the spring force less to cause a decrease in generator output. After the regulator adjustment has been made test the generator output with the regulator cover installed.

GENERATOR OUTPUT ADJUSTMENT
1. Adjustment screw.

Starting System

5P300 Electrical Tester.

NOTE: Make reference to Special Instruction Form No. SEHS7006 and to the instructions inside of the cover of the tester, when testing with the 5P300 Electrical Tester.

Use a D.C. Voltmeter to find starting system components which do not function.

Move the starting control switch to activate the starter solenoid. Starter solenoid operation can be heard as the pinion of the starter motor is engaged with the ring gear on the engine flywheel.

If the solenoid for the starter motor will not operate, it is possible that the current from the battery does not get to the solenoid. Fasten one lead of the voltmeter to the connection (terminal) for the battery cable on the solenoid. Put the other lead to a good ground. No voltmeter reading shows there is a broken circuit from the battery. More testing is necessary when there is a reading on the voltmeter.

The solenoid operation also closes the electric circuit to the motor. Connect one lead of the voltmeter to the solenoid connection (terminal) that is fastened to the motor. Put the other lead to a good ground. Activate the starter solenoid and look at the voltmeter. A reading of battery voltage shows the problem is in the motor. The motor must be removed for more testing. No reading on the voltmeter shows that the solenoid contacts do not close. This is an indication of the need for repair to the solenoid or an adjustment to be made to the starter pinion clearance.

Make a test by fastening one voltmeter lead to the connection (terminal) for the small wire at the solenoid and the other lead to the ground. Look at the voltmeter and activate the starter solenoid. A voltmeter reading shows that the problem is in the solenoid. No voltmeter reading shows that the problem is in the heat-start switch or wiring.

Fasten one voltmeter lead to the heat-start switch at the connection (terminal) for the wire from the battery. Fasten the other lead to a good ground. No voltmeter reading indicates a broken circuit from the battery. Make a check of the circuit breaker and wiring. If there is voltmeter reading, the malfunction is in the heat-start switch or in the wiring.

Fasten one lead of the voltmeter to the battery wire connection of the starter switch and put the other lead to a good ground. A voltmeter reading indicates a failure in the switch.

A starter motor that operates too slow can have an overload because of too much friction in the engine being started. Slow operation of the starter motor can also be caused by shorts, loose connections, and/or dirt in the motor.

Pinion Clearance Adjustment (Delco-Remy)

When the solenoid is installed, adjust the pinion clearance. Make the adjustment with the starter motor removed.

Bench test and adjust the pinion clearance at installation of solenoid as follows:

1. Install the solenoid without connector (1) from the MOTOR terminal on solenoid to the motor.

2. Connect a battery, of the same voltage as the solenoid, to the terminal (2), marked SW.

3. Connect the other side of battery to ground terminal (3).

CONNECTIONS FOR CHECKING PINION CLEARANCE
1. Connector from MOTOR terminal on solenoid to motor. 2. SW terminal. 3. Ground terminal.

PINION CLEARANCE ADJUSTMENT
4. Shaft nut. 5. Pinion. 6. Pinion clearance.

4. MOMENTARILY flash a jumper wire from the solenoid terminal marked MOTOR to the ground terminal. The pinion will shift into cranking position and will remain there until the battery is disconnected.

5. Push pinion towards commutator end to eliminate free movement.

6. Pinion clearance (6) is .33 to .39 in. (8.3 to 9.9 mm).

7. To adjust clearance remove the plug and turn shaft nut (4).

Pinion Clearance Adjustment (Prestolite)

There are two adjustments on this type motor. They are end play for the armature and pinion clearance.

End Play For The Armature

The correct end play for the armature is .005 to .030 in. (0.13 to 0.76 mm). The adjustment is made by adding or removing thrust washers on the commutator end of the armature shaft.

Pinion Clearance Adjustment

CONNECTIONS FOR ADJUSTMENT OF THE PINION CLEARANCE
1. Stud.

1. To adjust the pinion clearance, connect the solenoid to a 12 volt battery as shown. For a short moment, connect a wire from the "motor" stud of the solenoid to the stud at (1) in the commutator end. This moves the solenoid and drive into the cranking position.

Disconnect the wire.

NOTE: The drive is in the cranking position until the battery is disconnected.

2. Push the drive toward the commutator end of the motor to eliminate any slack movement in the linkage and measure the distance between the outside edge of the drive sleeve and the thrust washer. The distance (3) must be .020 to .050 in. (0.51 to 1.27 mm).

PINION CLEARANCE ADJUSTMENT
2. Adjusting nut. 3. Distance.

3. Remove the plug. Turn the adjusting nut (2) in or out as necessary to get this distance.

4. Install the plug.

Air Starting System

Pressure Regulating Valve

PRESSURE REGULATING VALVE (TYPICAL ILLUSTRATION)
1. Adjustment screw. 2. Regulator inlet. 3. Regulator outlet.

Use the procedure that follows to check and adjust the pressure regulating valve.

1. Drain the line to the pressure regulating valve or drain the air storage tank.

2. Disconnect the regulator from the starter control valve.

3. Connect an 8M2885 Pressure Gauge to the regulator outlet.

4. Put air pressure in the line or tank.

5. Check the pressure.

6. Adjust the pressure regulating valve to 100 to 150 psi (690 to 1030 kPa).

7. Remove the air pressure from the line or tank.

8. Remove the 8M2885 Pressure Gauge and connect the air pressure regulator to the line to the air starting motor.

Each engine application will have to be inspected to get the most acceptable starting results. Some of the factors that affect regulating valve pressure setting are: attachment loads pulled by engine during starting, ambient temperature conditions, oil viscosity, capacity of air reservoir, and condition of engine (new or worn).

The advantages of setting the valve at the higher pressures are increased torque for starting motor and faster rotation of engine. The advantage of setting the valve at the lower pressures is longer time of engine rotation for a given reservoir capacity of supply air.

Lubrication

Always use an air line lubricator with these Starters.

For temperatures above 32° F (0° C), use a good quality SAE 10 motor oil.

For temperatures below 32° F (0° C), use diesel fuel.

To maintain the efficiency of the starting motor flush it at regular intervals. Put approximately 1 pt. (0.5 litre) of diesel fuel into the air inlet of the starting motor and operate the motor. This will remove the dirt, water and oil mixture (gummy coating) from the vanes of the motor.

Air Starting Motor

The cylinder (12) must be assembled over the rotor (15) and on the front end plate (16) so the dowel hole (12B) and the inlet passages (12A) for the air are as shown in the rear view illustration of the cylinder and rotor. If the installation is not correct, the starter drive (42) will turn in the wrong direction.

Tighten the bolts (6) of the rear cover in small increases of torque for all bolts until all bolts are tightened to 20 to 25 lb. ft. (25 to 35 N·m).

Put a thin layer of lubricant on the lip of the seal (29) and on the outside of the collar (35), for installation of drive shaft (34). After installation of the shaft through the cover (28), check the lip of the grease seal (29). It must be turned correctly toward the drive gear (25). If the shaft turned the seal lip in the wrong direction, remove the shaft and install again. Use a tool with a thin point to turn the seal lip in the correct direction.

REAR VIEW OF THE CYLINDER AND ROTOR FOR CLOCKWISE ROTATION
12. Cylinder. 12A. Air inlet passages. 12B. Dowel hole. 15. Rotor.

AIR STARTER (INGERSOLL-RAND)
6. Bolt. 12. Cylinder. 15. Rotor. 16. Front end plate. 22. Gear case. 25. Drive gear. 28. Gear case cover. 42. Starter drive (pinion). 45. Drive housing. 49. Air inlet. 50. Deflector (air outlet). 51. Mounting flange on the drive housing.

Tighten the bolts (32) of the drive housing in small increases of torque for all bolts until all bolts are tightened to 100 lb. in. (11.3 N·m).

Check the motor for correct operation. Connect an air hose to the air inlet (49) and make the motor turn slowly. Look at the drive pinion (42) from the front of the drive housing (45). The pinion must turn clockwise.

Connect an air hose to the small hole with threads in the drive housing (45), near the gear case (22). When a little air pressure goes to the drive housing, the drive pinion (42) must move forward to the engaged position. Also, the air must get out through the other hole with threads nearer the mounting flange (51).

COMPONENTS OF THE AIR STARTER (INGERSOLL-RAND, SIZE 150 BMP, MODEL C OR E)
1. Motor housing cover. 2. Plug. 3. Plug. 3A. Plug. 6. Bolt (cap screw). 7. Lockwasher. 8. Gasket. 9. Rotor rear bearing. 10. Bearing retainer. 11. Rear end plate. 12. Cylinder. 13. Dowel. 14. Rotor vane. 15. Rotor. 16. Front end plate. 17. Rotor front bearing. 18. Motor housing. 19. Gear case gasket. 20. Rotor pinion. 21. Rotor pinion retainer. 22. Gear case. 23. Bearing ejecting washer. 24. Rear bearing for the drive shaft. 25. Drive gear. 25A. Thrust washer. 26. Key for the drive gear. 27. Front bearing for the drive shaft. 28. Gear case cover. 29. Grease seal for the drive shaft. 30. Cover seal. 31. Piston seal. 32. Bolt. 33. Lockwasher. 34. Drive shaft. 35. Drive shaft collar. 36. Piston. 36A. Piston ring. 37. Shift ring. 38. Shift ring retainer. 39. Shift ring spacer. 40. Piston return spring. 41. Return spring seat. 42. Starter drive (pinion). 43. Lockwasher. 44. Bushing for the bolts. 45. Drive housing. 46. Drive housing bushing. 47. Oiler felt for the bushing. 48. Oiler plug.