D348 INDUSTRIAL & MARINE ENGINES Caterpillar


Testing And Adjusting

Usage:

Troubleshooting

Troubleshooting can be difficult. On the following pages there is a list of possible problems. To make a repair to a problem, make reference to the cause and correction.

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 can not give all possible problems and corrections. The serviceman must find the problem and its source, then make the necessary repairs.

1. Contactor Switch for Water Temperature Does Not Activate Shutoff Solenoid.
2. Contactor Switch for Water Temperature Activates Shutoff Solenoid at Wrong Temperature.
3. Contactor Switch for Oil Pressure Fails to Activate Shutoff Solenoid.
4. Contactor Switch for Overspeed Fails to Activate Shutoff Solenoid.
5. Contactor Switch for Overspeed Activates Shutoff Solenoid at Wrong Speed.
6. Shutoff Solenoid Fails to Stop Engine.
7. Shutoff Solenoid Prevents Engine Start.
8. Clutch Will Not Engage (Slips), Heats or Lever Moves to Released Position.
9. Clutch Shaft Has Too Much End Play.
10. Clutch Bearings Have Short Service Life.
11. Electrical Gauges Give Wrong Readings.
12. 2301 Nonparallel Control System.
a. Engine Will Not Start.
b. Engine Overspeeds On Starts.
c. Engine Overspeeds After Operation At Rated Speed For Some Time.
d. Low Idle Speed Potentiometer Gives No Adjustment.
e. Engine Does Not Return To Low Idle When The Idle (Oil Pressure) Switch Opens.
f. Engine Speed Does Not Have Stability.
g. Speed Trim Potentiometer Gives No Adjustment.
h. Rated Speed Potentiometer Gives No Adjustment.
i. Load Sharing Is Not Correct.
j. Engine Speed Is Not Ishochronous.
13. 2301 Parallel Control System.
a. Engine Will Not Start.
b. Engine Overspeeds On Starts.
c. Engine Overspeeds After Operation At Rated Speed For Some Time.
d. Low Idle Speed Potentiometer Gives No Adjustment.
e. Engine Does Not Return To Low Idle When The Idle (Oil Pressure) Switch Opens.
f. Engine Speed Does Not Have Stability.
g. Speed Trim Potentiometer Gives No Adjustment.
h. Rated Speed Potentiometer Gives No Adjustment.
i. Load Sharing Is Not correct.
j. Engine Speed Is Not Isochronous.
k. System Does Not Have Stability When Paralleling Or In Parallel.
14. Woodward UG-8 Governors
a. Engine Speed Does Not Have Stability.
b. Fuel Control Response When The Engine Is Started Is Not Acceptable.
c. Engine Is Slow To Respond To A Change In Speed Setting or Load.
d. Load Sharing Between Paralleled Units Is Not Correct (One unit on zero droop all others on droop).
e. Load Sharing Between Paralleled Units Is Not Correct (all units on droop).
15. Automatic Start/Stop Systems.

Contactor Switch For Water Temperature Does Not Activate Shutoff Solenoid

Contactor Switch For Water Temperature Activates Shutoff Solenoid At Wrong Temperature.

Contactor Switch For Oil Pressure Fails To Activate Shutoff Solenoid.

Contactor Switch For Overspeed Fails To Activate Shutoff Solenoid.

Contactor Switch For Overspeed Activates Shutoff Solenoid At Wrong Speed.

Shutoff Solenoid Fails To Stop Engine.

Shutoff Solenoid Prevents Engine Start

Clutch Will Not Engage (Slips), Heats Or Lever Moves To Released Position.

Clutch Shaft Has Too Much End Play.

Clutch Bearings Have Short Service Life.

Electrical Gauges Give Wrong Readings.

Engine Will Not Start.

Engine Overspeeds On Starts.

Engine Overspeeds After Operation At Rated Speed For Some Time.

Low Idle Speed Potentiometer Gives No Adjustment.

Engine Does Not Return To Low Idle When The Idle (Oil Prssure) Switch Opens.

Engine Speed Does Not Have Stability.

Speed Trim Potentiometer Gives No Adjustment.

Rated Speed Potentiometer Gives No Adjustment.

Load Sharing Is Not Correct.

Engine Speed Is Not Isochronous.

Engine Will Not Start.

Engine Overspeeds On Starts.

Engine Overspeeds After Operation At Rated Speed For Some Time.

Low Idle Speed Potentiometer Gives No Adjustment.

Engine Does Not Return To Low Idle When The Idle (Oil Pressure) Switch Opens.

Engine Speed Does Not Have Stability.

Speed Trim Potentiometer Gives No Adjustment.

Rated Speed Potentiometer Gives No Adjustment.

Load Sharing Is Not Correct.

Engine Speed Is Not Isochronous.

System Does Not Have Stability When Paralleling Or In Parallel.

Engine Speed Does Not Have Stability.

Fuel Control Response When Engine Is Started Is Not Acceptable.

Engine Is Slow To Respond To A Speed Or Load Change.

Load Sharing Between Paralleled Units Is Not Correct (One unit on zero droop all others on droop).

Load Sharing Between Paralleled Units Is Not Correct (All units on droop).

Automatic Start/Stop System.

Woodward UG8 Dial Governor

Measuring Engine Speed

5P2150 Engine Horsepower Meter or4S6553 Instrument Group or1P5500 Portable Phototach Group


5P2150 ENGINE HORSEPOWER METER

The 5P2150 Engine Horsepower Meter can measure engine speed from the tachometer drive on the engine. Special Instruction Form No. SMHS7050 has instructions for its use.

Special Instruction Form No. SEHS7341 is with the 4S6553 Engine Test Group and gives instructions for the test procedure.


4S6553 INSTRUMENT GROUP
1p1. Differential pressure gauges. 2. Zero adjustment screw. 3. Lid. 4. Pressure gauge. 5. Pressure tap fitting. 6. Tachometer. 7. Manifold pressure gauge.

The 1P5500 Portable Phototach Group can measure engine speed from the tachometer drive on the engine. It also has the ability to measure engine speed from visual engine parts in rotation. Special Instruction Form No. SMHS7015 has instructions for its use.


1P5500 PORTABLE PHOTOTACH GROUP

High Idle Speed Adjustment

Connect a tachometer with good accuracy to the engine. Make reference to MEASURING ENGINE SPEED.

1. Start the engine and run to get the engine to the normal temperature of operation.

2. Use synchronizer control knob (5) to adjust the engine speed and check the high idle speed stop adjustment.


GOVERNOR ADJUSTMENTS (Typical Example)
1. Terminal lever. 2. Idler gear. 3. Load limit control. 4. Linkage. 5. Synchronizer control knob. 6. Gear. 7. Synchronizer indicator knob.

3. If the high idle speed is not correct, remove the dial plate.

NOTE: Make reference to the RACK SETTING INFORMATION for the correct high idle speed.

4. Loosen the setscrew on synchronizer indicator knob (7), remove tapered pin if equipped and remove the knob.

5. Pull gear (6) out of mesh with idler gear (2). Turn synchronizer control knob (5) until the correct high idle speed is reached.

6. To set the high idle speed stop, turn gear (6) clockwise until the stop pin on the gear makes contact with idler gear (2). Push gear (6) into mesh with idler gear (2).

7. Turn the synchronizer control knob counterclockwise to change the engine speed. Now turn the knob to the high idle stop and check the high idle adjustment.

8. Install the synchronizer indicator knob and the dial plate.

NOTE: Low idle speed is not adjustable, but will change as high idle adjustment is made. If low idle is not correct, an increase in high idle speed will increase low idle speed, and a decrease in high idle speed will decrease low idle speed.

Fuel Rack Adjustment

9S240 Rack Positioning Tool Group2P2977 Tool Group (Later Type)

1. Install a dial indicator and use the rack centering timing pin to zero the indicator as described for the standard engine Hydramechanical governor. See the FUEL SYSTEM (Rack Adjustment) information covered in the ENGINE TESTING AND ADJUSTING section of this manual.


FUEL RACK TRAVEL ADJUSTMENT (Later Type)
1. Stop screw. 2. Screw locknut


FUEL RACK TRAVEL ADJUSTMENT (Earlier Type)
1. Stop screw. 2. Locknut. 3. Lock.

2. Set the governor load limit control knob on 10. Using the lever on the governor terminal shaft, move the fuel rack from the FUEL OFF position toward the FUEL ON position until contact is made with adjusting stop screw (1), and read the rack setting gauge. Compare the rack travel value with that listed in the RACK SETTING INFORMATION.


NOTICE

Do not force the engine linkage toward increased fuel without first turning the load limit knob to 10.


3. If the full rack travel is not the value listed in the RACK SETTING INFORMATION loosen the adjusting screw locknut (2). Earlier type governors require that the lock (3) be raised so the adjusting screw can be turned freely.

4. Turn the adjusting screw counterclockwise to increase the fuel rack travel or clockwise to decrease the rack travel. When the fuel rack is correctly adjusted, lower the lock into the nearest notch and tighten the locknut.

Adjustments


NOTICE

Only competent personnel should attempt to adjust fuel rack settings and the governor. The low and high idle rpm, and rack setting dimensions for these engines, are listed in the RACK SETTING INFORMATION.


Governor Linkage Adjustment: D346 Engines 39J413-Up, D348 Engines 36J363-Up and D349 Engines 61P1-Up


GOVERNOR LINKAGE ADJUSTMENT D346 (39J413-Up), D348 (36J363-Up) and D349 (61P1-Up) Engines
1. Terminal lever is 2.25 in. (57.2 mm) long. 2. Terminal lever to horizontal is 30°. 3. Lower lever is 3.5 in. (88.9 mm) long. 4. Rod. 5. Lower lever to horizontal angle is 30°. Arrow indicates off direction.

1. With rack at shut off position and key in shaft put lower lever (3) on shaft. This should result in angle of 30° as shown at (5).

2. Put terminal shaft in shut off position.

3. Put terminal shaft lever (1) on terminal shaft at angle of 30° from horizontal as shown at (2).

4. Make rod (4) correct length so angles of levers are not changed.

Governor Linkage Adjustment: D346 Engines 39J1 thru 39J412 and D348 Engines 36J1 thru 36J362.

1P2385 Protractor Tool

With governor shaft at shutoff position, assemble terminal shaft lever (1) to the shaft at angle from vertical as shown. Adjust link (2) so the rack indicator reading from center position (zero position) is minus .077 ± .005 in. (1.96 ± 0.13 mm). Tool arrangement for establishing center position (zero position) is the same as for standard hydra-mechanical governor. See the topic Rack Setting in the BASIC ENGINE portion of this manual.

Illustrated here are three basic usages of 1P2385 Protractor Tool.

First: Vertical housing face-to-lever angle.

Second: Horizontal or level-to-lever angle.

Third: Lever-to-lever angle.


1P2385 PROTRACTOR TOOL USAGE
A-Angle setting indicator. B-Protractor plate edge aligned with lever. C-Vertical housing face and extension arm alignment. D-Level bubble. E-Angle setting indicator. F-Extension arm aligned with lever. G-Extension arm aligned with lever. H-Plate edge aligned with second lever. I-Angle setting indicator.

Install shims (4) under stop plate to obtain .020 in. (0.51 mm) clearance between the rack lever stop bolt (5) and stop plate with the governor lever in stop position.

Pin the adjustable link (2) to the rod end with pin (3).


GOVERNOR LINKAGE ADJUSTMENT D346 (39J1-39J412), D348 (36J1-36J362) Engines [Dimensions in inches (mm)]
1. Terminal shaft lever. 2. Adjustable link. 2. Roll pin. 4. Shims. 5. Rack lever stop bolt.

Compensating Adjustment

Although the governor may appear to be operating satisfactorily at no load, high overspeeds and underspeeds after load changes and slow return to normal speed are the results of incorrect compensation adjustments.

Make compensating adjustments after the temperature of the engine and the oil in the governor have reached normal operating values and with the engine running at no load conditions.


UG8 DIAL GOVERNOR
1. Nut. 2. Compensation pointer. 3. Plug.

1. Loosen the nut that holds the compensation pointer and move the pointer up as far as it will go. Tighten the nut.

2. Remove the plug from the base of the governor.

3. Use a wide blade screwdriver and engage the wide screwdriver slot in the needle valve. Turn the needle valve three or more turns in a counterclockwise direction.

4. Let the engine surge for approximately 30 seconds to help remove air from the governor.

5. Loosen the nut that holds the compensation pointer and move the pointer down as far as it will go. Tighten the nut.

6. Slowly turn the needle valve in a clockwise direction until the engine does not surge.

7. Check the number of turns the needle valve is open. To find the number of turns the needle valve is open, close the valve completely and make a note of the number of turns needed to close the valve.

8. Open the needle valve to the same position at which the engine did not surge.

9. Move the governor linkage to change the engine speed. If the engine does not surge, and the needle valve is 1/2 to 3/4 of a turn open, the governor adjustment is correct. Install the plug in the base. If the needle valve is more than 3/4of a turn open, do the steps that follow.

10. Loosen the nut that holds the compensation pointer and move the pointer up two marks on the pointer scale.

11. Turn the needle valve three or more turns in a counterclockwise direction.

12. Let the engine surge for approximately 30 seconds to help remove air from the governor.

13. Slowly turn the needle valve in a clockwise direction until the engine does not surge.

14. Check the number of turns the needle valve is open. To find the number of turns the needle valve is open, close the valve completely and make a note of the number of turns needed to close the valve.

15. Open the needle valve to the same position at which the engine did not surge.

16. Move the governor linkage to change the engine speed.

If the engine does not surge, and the needle valve is 1/2 to 3/4 of a turn open, the governor adjustment is correct. Install the plug in the base. If the needle valve is more than 3/4 of a turn open do Steps 10 thru 16 again.

A needle valve that is opened less than 1/2 turn will cause the engine to be slow to return to normal speed after a load change.

If the compensation pointer is too far toward the maximum position, the engine speed change will be too great when the load changes.

Woodward EG-3P Governor Actuator

Adjustments

Setting Fuel Rack Limit Stop

9S240 Rack Positioning Tool Group2P2977 Tool Group (Later Type)

1. Install a dial indicator and use the rack centering timing pin to zero the indicator as described for the standard engine Hydramechanical governor. See the FUEL SYSTEM (Rack Adjustment) information covered in the ENGINE Testing and Adjusting section of this manual.


FUEL RACK TRAVEL ADJUSTMENT (Later Type)
1. Stop screw. 2. Locknut.


FUEL RACK TRAVEL ADJUSTMENT (Earlier Type)
1. Stop screw. 2. Locknut. 3. Lock.

2. Using the lever on the governor terminal shaft, move the fuel rack from the FUEL OFF position toward the FUEL ON position until contact is made with adjusting stop screw (1), and read the rack setting gauge. Compare the rack travel value with that listed in the RACK SETTING INFORMATION.

3. If the fuel rack travel is not the value listed in the RACK SETTING INFORMATION, loosen the adjusting screw locknut (2). Earlier type governor requires the lock (3) be raised so the adjusting screw can be turned freely.

4. Turn the adjusting screw counterclockwise to increase the fuel rack travel or clockwise to decrease the rack travel. When the fuel rack is correctly adjusted, lower the lock into the nearest notch and tighten the locknut.

Linkage Adjustments (D346 and D348 Engines)

1P2385 Protractor Tool

1. Place governor terminal shaft at shut off position.

2. Install terminal shaft lever (1) at angle shown from horizontal.

3. Adjust link (2) so rack lever assembly (3) makes the angle shown from horizontal.

NOTE: The angle will position the fuel rack in the shut off (zero) position. Tool arrangement for checking second tooth centerline position (zero position) is the same as for standard hydramechanical governor.

Illustrated here are three basic usages of 1P2385 Protractor Tool.

First: Vertical housing face-to-lever angle.

Second: Horizontal or level-to-lever angle.

Third: Lever-to-lever angle.


1P2385 PROTRACTOR TOOL USAGE
A-Angle setting indicator. B-Protractor plate edge aligned with lever. C-Vertical housing face and extension arm alignment. D-Level bubble. E-Angle setting indicator. F-Extension arm aligned with lever. G-Extension arm aligned with lever. H-Plate edge aligned with second lever. I-Angle setting indicator.


EG-3P ACTUATOR LINKAGE ADJUSTMENT [Dimensions in inches (mm)]
1. Terminal shaft lever. 2. Adjustment link. 3. Rack lever assembly.

Linkage Adjustment (D349 Engine)

1P2385 Protractor Tool

1. Turn terminal shaft to shut off position and install terminal shaft lever (1) at an angle of 30° from horizontal.

NOTE: 1P2385 Protractor Tool usage is illustrated earlier in this topic.

2. Move the rack to shut off position. Install the key in shaft and the lower lever (3). This should result in lever angle of 30° from horizontal.


EG-3P ACTUATOR LINKAGE ADJUSTMENT (D349 Engine)
1. Terminal shaft lever is 2.25 in. (57.2 mm) long. 2. Rod. 3. Lower lever is 3.5 in. (88.9 mm) long. Arrows indicate off direction.

3. Make the rod (2) the correct length so the angles are not changed when terminal shaft lower levers are in shut off position.

2301 Control Systems

NOTE: For information on earlier 2301 control systems make reference to INDUSTRIAL DIVISION ENGINE DATA SHEET Form No. LEO21991-01.

Magnetic Pickup


MAGNETIC PICKUP
1. Clearance dimension. 2. Magnetic pickup. 3. Wires. 4. Locknut. 5. Flywheel gear. 6. Adapter.

1. Crank the engine. Use a voltmeter to check the output of the magnetic pickup. Minimum cranking voltage is 1.0V. Minimum voltage at 1500 rpm is 10V. If these voltages are not correct make an adjustment as follows:

2. Loosen locknut (4).

3. Turn magnetic pickup (2) in until it just has contact with flywheel (5).

4. Turn the magnetic pickup out 1/2 revolution. This will make clearance dimension (1) .022 to .033 in. (0.56 to 0.84 mm).

5. Tighten the locknut to 50 ± 10 lb. ft. (70 ± 14 N·m).

6. Do Step 1 again. If the voltages are still not correct make replacement of the magnetic pickup.

Woodward EG-3P Governor Actuator

Check for Actuator Coil Resistance

1. Remove the connection plug from the EG-3P actuator.

2. There are four terminals on the actuator. They have marks "A", "B", "C" and "D". Connect the probes of an ohmmeter between terminals "A" and "B". Put a jumper wire between terminals "C" and "D".


EG-3P ACTUATOR

3. If the coil resistance is not 30 to 40 ohms make a replacement of the actuator.

Potentiometer Adjustment (Parallel Or Nonparallel Control)


2301 PARALLEL CONTROL
1. Speed potentiometer. 2. Stability potentiometer. 3. Gain potentiometer. 4. Ramp time potentiometer. 5. Low speed potentiometer. 6. Load gain potentiometer. 7. Droop potentiometer. 8. De-droop potentiometer. 9. Load signal jacks.

Speed Potentiometer

Turn speed potentiometer (1) clockwise to increase or counterclockwise to decrease the full load rpm of the engine.

Stability and Gain Potentiometers

1. Connect a DC voltmeter to terminals 5 (-) and 6 (+) on the parallel control [terminals 6 (-) and 17 (+) on the nonparallel control].

2. Start the engine. Run the engine until the coolant temperature is normal.

3. Turn gain potentiometer (3) clockwise until the voltmeter does not have stability.

4. Turn stability potentiometer (2) either direction until the voltmeter has stability.

5. Do Steps 3 and 4 several times until the stability potentiometer will not give the voltmeter stability.

6. Turn the gain potentiometer a small amount counterclockwise. Adjust the stability potentiometer as necessary.

Ramp Time Potentiometer

Turn ramp time potentiometer (4) clockwise to increase or counterclockwise to decrease the amount of time it takes the engine to accelerate from low idle to full load rpm.

Low Speed Potentiometer

1. Make sure there is an open between terminals 9 and 10 (terminals 14 and 15 on the nonparallel control).

2. Turn low speed potentiometer clockwise to increase or counterclockwise to decrease the low idle rpm.

Load Gain Potentiometer

NOTE: Stability and gain potentiometers must be correctly adjusted first.

1. Put the probes of a voltmeter in the load signal jacks (9).

2. Run the engine in single unit operation until the coolant temperature is normal.

3. Put a full load on the generator. Adjust load gain potentiometers until the load signal reading on the voltmeter is 8V. If it is not possible to put a full load on the generator keep the ratio between the load and the voltage signal constant. For example: if the load on the generator is 1/2 of its rated capacity adjust the load gain potentiometer to get a load signal of 4V.

4. Do Steps 1, 2 and 3 to all the units in the system. The load signal for each unit in the system must be the same.

5. If any of the units in the system have stability problems at this load gain setting, decrease the setting for each unit a small amount. Keep the load signal for each unit in the system the same.

6. If the load signal at full load is decreased to 3V in Step 5 and the system still has a stability problem do the steps that follow.

7. Parallel all of the units in the system at no load.

8. If the system has instability turn the stability potentiometer of each unit one mark counterclockwise. Do this until the system has stability.

9. Put a load on the system. If the system has instability turn the stability potentiometer of each unit one mark counterclockwise. Do this until the system has stability.

NOTE: The generator voltage regulator response may be too fast. Use a manual voltage regulator. If this stops the instability, slow down the response of the generator voltage regulator.

Droop Potentiometer

The amount of speed droop adjustment available will vary with the application from 0 to 13%. The desired speed droop will be different for different applications. Speed droop is the percent difference between the engine speed at no load and full load. To calculate speed droop use the formula:

1. Get the desired speed droop for the application.

2. Multiply the full load speed by the desired speed droop. Add the number from this multiplication to the full load speed to get the no load speed.

3. Run the engine until the coolant temperature is normal.

4. Adjust the engine speed to get the no load speed for Step 2.

5. Connect a known load to the engine. The load must be less than the full capacity of the engine. Make a record of the decrease in engine speed.

NOTE: Load on engine or load on generator can be used.

6. Make a ratio between the load on the engine and the full load capacity of the engine. This ratio must be the same as the ratio between the decrease in engine speed from Step 5 and the number from the multiplication in Step 2. For example:

7. If the ratios are not the same an adjustment of the speed droop is necessary. Remove the load and stop the engine. If the engine speed decreases too much according to the ratio, decrease the amount of speed droop. If the decrease in engine speed is not enough increase the amount of speed droop.

8. Turn droop potentiometer (7) clockwise to increase or counterclockwise to decrease the amount of speed droop.

De-Droop Potentiometer

1. Set the system for isochronous operation at the desired rpm. Droop potentiometer at zero droop.

2. Put the maximum available load on the unit, up to 100% of rated capacity.

3. If there is a change in rpm use the de-droop potentiometer to return the engine to the desired rpm.

Governor Air Actuators

2N6006 Actuator

Air Pressure Adjustment

1. Remove linkage (1) between actuator and governor.


ACTUATOR LINKAGE
1. Linkage.

2. Start the engine. Let the engine run until it is warm.

3. Check high and low idle rpm with a tachometer. If necessary, make adjustments to the governor high and low idle screws to get correct rpm.

4. Stop the engine.

5. Install an air gauge (2) in the line between the actuator air control lever (3) and the actuator (4).


ACTUATOR AIR PRESSURE ADJUSTMENT
2. Air gauge. 3. Actuator air control lever. 4. Actuator. 5. Nut. 6. Plunger. 7. Screw.

6. Start the engine.

7. Check the air pressure to the actuator. Minimum air pressure at high idle must be 65 psi (450 kPa). Maximum air pressure must not be more than 80 psi (550 kPa).

8. Put the governor hand control lever in the low idle position.

9. Move the actuator air control lever (3) slowly to the high idle position. Look at the plunger (6). The plunger must start to move at 10 psi (70 kPa).

NOTE: If the plunger (6) moves at less than 10 psi (70 kPa) make the preload higher. If more than 10 psi (70 kPa) air pressure is needed to move the plunger, make the preload lower.

10. Return the actuator air control lever (3) to the low idle position to change preload.

11. Turn screw (7) out until nut can be turned.

12. Turn nut (5) clockwise to make preload higher. Turn nut counterclockwise to make preload lower.

13. When plunger (6) moves at 10 psi (70 kPa) air pressure, turn the screw in until nut can not be turned.

NOTE: If necessary, turn nut until screw is in line with next notch in nut.

14. Install linkage between actuator and governor.

Setting Low Idle Stop


ACTUATOR LINKAGE ADJUSTMENT
1. Linkage.

1. Start the engine. Let the engine run until it is warm.

2. Put the actuator air control lever in the low idle position.

3. Install a tachometer and check the low idle rpm.

4. If low idle rpm is not correct, remove linkage (1) between actuator and governor to make adjustment.

5. Make linkage (1) shorter to decrease rpm. Make the linkage longer to increase rpm.

Setting High Idle Stop

1. Warm up engine.

2. Remove two setscrews (5) and turn the two high idle screws (4) out several turns.

3. Move the governor hand control lever to the high idle position.

4. Move the actuator air control lever (2) slowly to the high idle position.


ACTUATOR LINKAGE ADJUSTMENT
1. Linkage.

5. Turn the high idle screws (4) in until they make contact with the plunger (3).

6. Install the two setscrews (5) to hold the high idle screws.

7. Return the actuator air control lever (2) to the low idle position.

8. Install a tachometer.

9. Make the governor high idle 30 rpm higher.

NOTE: Step 9 lets the actuator high idle stop control the engine rpm.

10. Return the governor hand control lever to the low idle position.


HIGH IDLE ADJUSTMENT
2. Actuator air control lever. 3. Plunger. 4. High idle screws. 5. Setscrews.

11. Move the actuator air control lever (2) to the high idle position.

12. Check the engine high idle rpm.

13. If necessary, make small adjustments to the actuator high idle screws (4) to get correct rpm.

NOTE: Turn actuator high idle screws the same amount. The plunger must contact both high idle screws at the same time.

14. Check linkage between governor and cross shaft. The length of rod (6) and angle (7) of governor lever should be as shown.


GOVERNOR LINKAGE
6. Rod should be 16.58 in. (421.1 mm). 7. Angle of governor lever to horizontal should be 15 ± 5°.

1N9318 Actuator

Air Pressure Adjustment


ADJUSTMENT OF ACTUATOR AIR PRESSURE
1. Air gauge. 2. Actuator air control lever. 3. Actuator. 4. Plunger. 5. Setscrew. 6. Screw. 7. Nut.

1. Start the engine. Let the engine run until it is warm.

2. Check high and low idle rpm with a tachometer. If necessary, make adjustments to the governor high and low idle screws to get correct rpm.

3. Stop the engine.

4. Install an air gauge (1) in the line between the actuator air control lever (2) and the actuator (3). See illustration.

5. Start the engine.

6. Check the air pressure to the actuator. Minimum air pressure at high idle must be 65 psi (450 kPa). Maximum air pressure must not be more than 80 psi (550 kPa).

7. Put the governor hand control lever in the low idle position.

8. Move the actuator air control lever (2) slowly to the high idle position. Look at the plunger (4). The plunger must start to move at 10 psi (70 kPa) air pressure.

NOTE: If plunger (4) moves at less than 10 psi (70 kPa), make the preload higher. If more than 10 psi (70 kPa) air pressure is needed to move the plunger, make the preload lower.

9. Return the actuator air control lever (2) to the low idle position to change preload.

10. Remove setscrew (5) and turn screw (6) out until nut (7) can be turned.

11. Turn nut (7) clockwise to make the preload higher. Turn nut counterclockwise to make the preload lower.

Shutoff And Alarm System Components

Contactor Switch For Oil Pressure

3P1564 Pressure Gauge (0 to 60 psi).3B7734 Pipe Nipple, 1/8 in. X 3.5 in.3B6483 Cap.Two 3B7263 Pipe Nipples, 1/8 in. X 2 in.Two 3B9389 Shutoff Cock Fittings.Two 1F9369 Tees.44914 Tee.Two 5K3772 Hose Assemblies.8S4627 Circuit Tester.


TEST EQUIPMENT
1. 3P1564 Pressure gauge (0 to 60 psi). 2. 3B7734 Pipe nipple. 3. 3B6483 Cap. 4. Oil supply line. 5. 3B7263 Pipe nipple. 6. 3B9389 Shutoff cock fitting. 7. 3B9389 Shutoff cock fitting. 8. 1F9369 Tees. 9. 5K3772 Hose assemblies. 10. 44914 Tee.

Test Procedure

1. Remove the cover of the contactor switch and disconnect the wires from the normally closed (B or Blue) terminal.

2. Disconnect the oil supply line from the contactor switch and install the test equipment as shown.

3. Connect the 5K3772 Hose from tee (10) to the contactor switch. Put the end of the other 5K3772 Hose in a pan.

4. Connect the 8S4627 Circuit Tester between the common terminal and the normally closed terminal. The light of the circuit tester will be activated.

5. Close shutoff fitting (7) and open shutoff fitting (6).

6. Look at the pressure gauge, start the engine and run it at low idle rpm. The light must go out, with an increase in oil pressure, at the specification of the switch.

7. Close shutoff fitting (6) and slowly open shutoff fitting (7). The light must be activated, with a decrease in oil pressure, at the specification of the switch.

8. Stop the engine.

9. Connect the wire(s) to the normally closed terminal.

10. On contactor switches with a button or a control knob either push the button or turn the knob to the OFF position.

11. Close shutoff fitting (7) and open shutoff fitting (6).

12. Start the engine and run it at low idle rpm.

13. Put a jumper wire between the common terminal and the normally closed terminal. This will check the system beyond the contactor switch.

14. Remove the jumper wire.

Adjustment of Earlier Type Switch


CONTACTOR SWITCH FOR OIL PRESSURE (Earlier Type)
11. Adjustment screw. 12. Main spring.

1. Turn adjustment screw (11) counterclockwise to make a decrease in the tension of main spring (12).

2. Disconnect the wires from the normally closed terminal of the switch.

3. Start the engine and run it at low idle rpm.

4. Close shutoff fitting (6) and slowly open shutoff fitting (7) until the pressure gauge shows the pressure specification at which the switch must close with a decrease in pressure. Close shutoff fitting (7).

5. Make sure the control knob is in RUN position. If so equipped.

6. Connect the 8S4627 Circuit Tester between the common terminal and the normally closed terminal. The light of the circuit tester must not be activated.


WIRING CONNECTIONS
A. Normally open terminal. B. Common terminal. C. Normally closed terminal.

7. Turn screw (11) clockwise until the light of the circuit tester is activated.

8. To check the adjustment, close shutoff fitting (7) and open shutoff fitting (6).

9. Connect the wires to the normally closed terminal.

10. Close shutoff fitting (6) and slowly open shutoff fitting (7) until the engine stops or the alarm operates.

11. The pressure gauge must show the correct pressure specification of the switch as the engine stops or the alarm operates.

Adjustment of Micro Switch Type

1. Loosen locknut (16) and turn adjustment screw (14) counterclockwise to make a decrease in the tension of spring (15).


CONTACTOR SWITCH FOR OIL PRESSURE (Micro Switch Type)
13. Set for start button. 14. Adjustment screw. 15. Spring. 16. Locknut. 17. Contact button.

2. Disconnect the wires from the normally closed terminal of the spring.

3. Start the engine and run it at low idle rpm.

4. Close shutoff fitting (6) and slowly open shutoff fitting (7) until the pressure gauge shows the pressure specification at which the switch must close with a decrease in pressure. Close shutoff fitting (7).

5. Make sure the set for start button (13) is in the RUN position.

6. Connect the 8S4627 Circuit Tester between the common terminal and the normally closed terminal. The light of the circuit tester must not be activated.

7. Turn screw (14) clockwise until the light of the circuit tester is activated.

8. Tighten the locknut.


WIRING CONNECTIONS
D. Normally closed B terminal. E. Normally open W terminal. F. Common R terminal.

9. To check the adjustment, close shutoff fitting (7) and open shutoff fitting (6).

10. Connect the wires to the normally closed terminal.

11. Close shutoff fitting (6) and slowly open shutoff fitting (7) until the engine stops or the alarm operates.

12. The pressure gauge must show the correct pressure specification of the switch as the engine stops or the alarm operates.

Contactor Switch For Water Temperature

Fabricated heat sink.2F7112 Thermometer.3J5389 Plug.8S4627 Circuit Tester.

Method of Checking

1. Make a heat sink as shown. Material can be brass, steel or cast iron. Drill 23/32 in. hole through the plate and use a tap to make 1/2 in. NPT threads.

2. Put marks on the two contactor wires that connect the contactor to the circuit. Disconnect the two wires.


HEAT SINK [Dimension in inches (mm)]

3. Remove the contactor and install a 3J5389 Plug. Install the contactor switch in the heat sink.

4. Put the heat sink and contactor in water as shown. Use blocks to support the heat sink at surface level.

5. Connect the 8S4627 Circuit Tester between the wires that connected the contactor to the circuit.


TEST OF CONTACTOR SWITCH
1. 2F7112 Thermometer. 2. Fabricated heat sink.

6. Put the 2F7112 Thermometer in the water.

7. Use a torch to heat the water to the temperature range at which the contactor must activate. If the circuit tester light does not come on within the temperature range given in the specifications make a replacement of the contactor.

Rack Shut-Off Solenoid

The governor plunger shaft initial adjustment of distance from shaft shoulder-to-plate should be .70 in. (17.8 mm).

Effective travel can be measured with rack setting gauges to be sure rack is moved to shutoff position. Make an on engine check with a 30 amp ammeter to be sure only the hold in windings are energized when the rack is held by the solenoid in shut-off position. Current draw should be less than 2 amp.


PLUNGER SHAFT ADJUSTMENT
1. Shoulder-to-plate distance .70 in. (17.8 mm). 2. Effective travel .62 in. (15.7 mm). 3. Starting position of plunger plate from mounting flange is .44 in. (11.2 mm) to measure effective travel of plunger.

Shut-Off Valve (Water Temperature)

3J5389 Plug.8B4509 Connector.3B9388 Connector.9M6543 Hose Assembly.4D6949 Hose Assembly.3B7764 Reducing Bushing.Heat Sink.

NOTE: See the topic Contactor Switch for Water Temperature in TESTING AND ADJUSTING for instructions to make a heat sink.

1. Remove oil lines.

2. Remove shut-off valve and install the 3J5389 Plug.

3. Install the oil lines using the bushing, hoses and connectors.

4. Start the engine and let it run at low idle.


SHUT-OFF VALVE (WATER TEMPERATURE)

5. Put the heat sink and the shut-off valve in water. Use a torch to make the water hot and, by using a thermometer, take not of the temperature at which the engine stops.

6. Install a new valve if necessary.

NOTE: If engine does not stop, look for a defect in the contactor switch for oil pressure.

Contactor Switch For Overspeed

The original setting of the contactor switch for overspeed will stop the engine when the engine rpm is more than 18% above full load rpm. DO NOT check the adjustment of the contactor switch on the engine.

Off Engine Adjustment

4S6553 Engine Test Group.8S4627 Circuit Tester.5L2277 Adapter.Reversible Variable Speed Drill.

1. Connect the 1P7443 or 4S6991 Tachometer of the 4S6553 Engine Test Group to the tachometer generator (2).

2. Connect the 5L2277 Adapter (3) to the contactor switch and tachometer generator (2).

3. Install variable speed drill (4) to the adapter a shown.

4. Connect the 8S4627 Circuit Tester (5) between the NO and C terminals of the contactor switch. The light must be off. If the light is on, push reset button (6).

5. Gradually make an increase in the rpm. Read the rpm on the tachometer at the moment the light of the circuit tester is activated. The reading will give the engine rpm (2 rpm on the meter for each rpm the input shaft is turned).


CHECKING CONTACTOR SWITCH FOR OVERSPEED
1. 4S6553 Engine Test Group. 2. Tachometer generator. 3. 5L2277 Adapter. 4. Variable speed drill. 5. 8S4627 Circuit Tester.

6. If needed, make an adjustment to the contactor switch by loosening lock screws (7). Turn the cap clockwise to lower the overspeed setting. Tighten the lock screws.

7. To check other components in the circuit, put a jumper wire between the C and NO terminals of the contactor switch.


OVERSPEED CONTACTOR SWITCH
6. Reset button. 7. Lock screws.

Overspeed Control Adjustment

4S6553 Engine Test Group.6L2211 Tachometer Drive Group.FT907 Drive Adapter.Reversible Variable Speed Drill.

Adjustment of the overspeed control is made at the factory and must not be changed unless the carrier assembly has been disassembled or the adjustment changed in some way. The original setting of the overspeed control will stop the engine when the engine rpm is more than 18% above full load rpm. DO NOT check the adjustment of the overspeed control on the engine.

1. Remove the engine shutoff control and reset cable from the engine.

2. Connect the 1P7443 or 4S6991 Tachometer (part of 4S6553 Engine Test Group) to 6L2211 Tachometer Drive Group (E) on control (A).

3. Use FT907 Adapter (C) and reversible variable speed drill (D) to drive the control as shown.

NOTE: When adjustment or check of the overspeed control is made and the oil pressure reset plunger is not pushed in, a low oil pressure shutoff action will be the result.


TEST OF OVERSPEED CONTROL
A. Shutoff control. B. 4S6553 Engine Test Group. C. FT907 Adapter. D. Reversible variable speed drill. E. 6L2211 Tachometer Drive Group.


NOTICE

All shutoff controls must be turned counterclockwise.


4. Read the rpm on the tachometer at the moment the control is activated. The reading will give the engine rpm (2 rpm on the scale for each rpm the input shaft is turned).

5. The control is to activate at a rpm 18% higher than the full load rpm.


Start, Stop Arrangement 8L5967 needs overspeed to activate at 1500 ± 25 prm.


ADJUSTMENT
1. Carrier assembly. 2. Weight adjustment screw. 3. Plug.

6. If an adjustment is needed, remove plug (3). If necessary, turn the drive shaft of the shutoff until the screw (2) is in alignment with the hole for plug (3).

7. Use a screwdriver to make the adjustment to the overspeed carrier assembly (1). One full turn of screw (2) will change the maximum overspeed limit 45 to 50 rpm. Turn the screw counterclockwise to make the setting lower.

8. Check the setting of the overspeed control again after the adjustment is made.

Electronic Speed Switch (Earlier)


ELECTRONIC SPEED SWITCH (EARLIER)
1. Cover.

Overspeed Adjustment

1. Remove cover (1). Make a temporary connection between terminals 1 and 2 of the speed switch.

2. Make reference to ENGINE SPEED MEASUREMENT. Use one of the methods given to measure the engine speed.

3. Start the engine. Make reference to the overspeed adjustment chart. Slowly increase the speed of the engine. The engine must stop at approximately 75% of the overspeed setting according to the rated full load speed of the engine. For example if the rated full load speed is 1800 rpm, the engine should stop at 1593 rpm.

4. If the speed switch does not stop the engine at the correct overspeed test rpm remove screw (3). Use a small screwdriver to turn the adjustment screw behind screw (3).

NOTE: Turn the adjustment screw clockwise to increase or counterclockwise to decrease the rpm at which the engine will stop.


ADJUSTMENT LOCATIONS
2. Screw. 3. Screw.

Cranking Adjustment

NOTE: Some earlier electronic speed switches do not have a cranking adjustment.

1. If the starter motor pinion does not move away from the flywheel at 600 rpm remove screw (2). Use a small screwdriver to turn the adjustment screw behind screw (2).

NOTE: Turn the adjustment screw clockwise to increase or counterclockwise to decrease the rpm at which the starter motor pinion moves away from the flywheel.

Electronic Overspeed Switch

Wiring Diagram


SHUTOFF SYSTEM WIRING DIAGRAM
1. Oil pressure switch. 2. Water temperature contactor. 3. Time delay switch. 4. Diode assembly. 5. 75% verify button. 6. Reset button. 7. "LED" overspeed light. 8. Seal screw plug (overspeed). 9. Seal screw plug (crank terminate). 10. Rack solenoid. 11. Magnetic pick-up. 12. Engine flywheel. 13. Voltage input. 14. Locknut. 15. Air gap.

Troubleshooting Procedure (Overspeed)

Troubleshooting Procedure (Crank Terminate)

Procedure A

Overspeed Setting Calibration


ELECTRONIC OVERSPEED SWITCH
5. Verify button. 6. Reset button. 7. "LED" overspeed light. 8. Seal screw plug (overspeed). 9. Seal screw plug (crank terminate).

1. Remove lockwire and seal from seal screws (8 & 9). Remove seal screw (8) from access hole for overspeed adjustment screw.

2. Use a small screwdriver and lightly turn O.S. (overspeed) adjustment potentiometer twenty turns in the direction of "MAX ARROW" (clockwise).

NOTE: The overspeed adjustment screw is made so that it can not cause damage to the potentiometer or be removed if the adjustment screw is turned too much.

3. Run engine 75% of desired overspeed setting rpm. Make reference to the SPEED SPECIFICATION CHART.

4. With engine at 75% of overspeed setting rpm, push VERIFY pushbutton (5) and hold in. Turn O.S. (overspeed) adjustment potentiometer in the direction opposite of "MAX ARROW" (counterclockwise) slowly until "LED" opverspeed light (7) comes on. Engine will shut down if speed switch is connected to the fuel shutoff solenoid and/or air inlet shutoff solenoids.

5. To reset speed switch, push in reset button (6). Air inlet shutoffs must be manually reset.

6. Slowly turn O.S. (overspeed) adjustment potentiometer approximately one turn clockwise and do Steps 3, 4 and 5 again.

NOTE: More adjustment may be needed to get the correct setting. Turn adjustment potentiometer clockwise to increase speed setting and counterclockwise to decrease speed setting. Turn adjustment potentiometer very slowly only a small amount at a time until adjustment is correct.

7. When the speed setting is correct, install seal screw (8) for overspeed adjustment hole and install lockwire and seal.

Procedure B

Magnetic Pickup Adjustment


MAGNETIC PICK-UP
12. Engine Flywheel. 14. Locknut. 15. Air gap.

1. Stop engine.

2. Loosen magnetic pick-up locknut (14).

3. Turn the magnetic pick-up clockwise until contact is made with the teeth of the engine flywheel ring gear (12).

4. Turn the magnetic pick-up counterclockwise onehalf turn. This will give approximately .022 to .033 in. (0.56 to 0.84 mm) clearance at location (15), between the end of the magnetic pick-up and the teeth of the flywheel ring gear.

5. After the clearance is correct, tighten the magnetic pick-up locknut to a torque of 50 ± 10 lb. ft. (70 ± 14 N·m).

NOTE: Be sure the magnetic pick-up does not turn when the locknut is tightened.

Procedure C

Crank Terminate Speed Adjustment

1. Remove lockwire and seal from seal screws (8 & 9). Remove seal screw (9) from access hole for crank terminate adjustment screw.

2. Use a small screwdriver and lightly turn C.T. (crank terminate) adjustment potentiometer twenty turns in the direction of "MAX ARROW" (clockwise).

NOTE: The crank terminate adjustment screw is made so that it can not cause damage to the potentiometer or be removed if the adjustment screw is turned too much.

3. Turn the crank terminate adjustment potentiometer twelve turns in a direction opposite of "MAX ARROW" (counterclockwise) for an approximate crank terminate setting.

4. Start engine and make a note of the speed at which the starter disengages. See the SPEED SPECIFICATION CHART for the correct crank terminate speed.

NOTE: If setting is not correct do Steps 5 and 6. If setting was correct do Step 7.

5. Stop engine and turn adjustment potentiometer (clockwise to increase and counterclockwise to decrease) crank terminate speed.

6. Start and make a note of the speed at which the starter disengages. If needed, make more small adjustments until the crank terminate speed is correct.

7. Install seal screw (9) for crank terminate adjustment hole and install lockwire and seal.


ELECTRONIC OVERSPEED SWITCH
5. Verify button. 6. Reset button. 7. "LED" overspeed light. 8. Seal screw plug (overspeed). 9. Seal screw plug (crank terminate).

Procedure D

Overspeed Verify Test

1. Run engine at rated speed, push verify button (5) in for a moment. This will cause the speed switch to activate and shut down the engine.

NOTE: Any time the engine speed is 75% or more of the overspeed setting, the engine will shut down if the verify button is pushed.

EXAMPLE: For an engine with a rated speed of 1500 rpm the overspeed setting is 1770 rpm. The overspeed verify test will shut down the engine at 75% of the overspeed setting of 1770 rpm. In this example 75% of 1770 rpm is 1328 rpm. If the verify button is pushed at an engine speed of 1328 rpm or above the engine will shut down.

The "LED" overspeed light (7) will come on and stay on until the reset button is pushed after an overspeed switch shut down. To restart the engine, push in reset button (6) for a moment. This will reset the speed switch and the rack shutoff solenoid. The "LED" overspeed light (7) will go off. The air inlet shutoff must be manually reset.

NOTE C: To verify overspeed shutdown system operation, push in for a moment the verify push button. The engine must shut down at 75% or more of overspeed setting.

NOTE D: Input voltage: Maximum 37 VDC Minimum 8 VDC.

NOTE E: The engine overspeed setting rpm is 118% of rated engine rpm.

NOTE F: The magnetic pick-up frequency (HZ) at the overspeed or cranking termination setting is calculated with the formula that follows:

If the rated speed of the engine is other than shown in the chart, the magnetic pick-up frequency for the overspeed setting can be found according to NOTES E and F.

If a 2301 Governor is used, only one magnetic pick-up is needed. Use the magnetic pick-up from the overspeed group. Connect the wires from the magnetic pick-up to the overspeed switch and then connect wires from the speed switch to the 2301 Governor. The overspeed switch can be installed close to the 2301 Governor if needed.

To reset overspeed switch, push in reset button for a moment.

Power Takeoff Clutches

Clutch Adjustment


POWER TAKEOFF CLUTCH (Typical Illustration)

1. Disconnect linkage (if so equipped) from the clutch lever. Fasten a spring scale to the clutch lever at the distance, from the lever shaft center, shown in the chart.

2. Look at the spring scale. Keep the angle between the scale and the lever at 90°. Pull the lever with the spring scale until the clutch engages. Make reference to the chart to find the correct amount of pull for the clutch assembly.

3. If the pull needed to engage the clutch is not correct, make an adjustment as follows:

4. Remove the inspection plate from the clutch housing.

5. Turn the clutch until lock pin (1 or 2) can be seen.

6. Release push type lock pin (1) or pull type lock pin (2). Turn the adjustment ring and check the pull needed to engage the clutch again.

NOTE: Turn the adjustment ring clockwise, as seen from the rear of the clutch, to increase the pull needed. Turn it counterclockwise to decrease the pull needed.


CLUTCH ADJUSTMENT
1. Lock pin (push type). 2. Lock pin (pull type).

Assembly Adjustments

End Play For Shaft Bearings

1. With dry bearings installed on the shaft install the shaft in the housing.

2. Install the retainer. Tighten the retainer (nut or shim type) until 60 lb. in. (6.8 N·m) is needed to keep the shaft in rotation.

3. With shim type retainer measure the space between the retainer and the carrier. Add .013 in. (0.33 mm) to this measurement. Install this amount of shims between the retainer and the carrier. With nut type retainers turn it out the number of notches shown on the chart.

4. Hit the output end of the clutch shaft with a soft hammer. This will cause the front bearing cup to move against the retainer.

5. Check the shaft end play with a dial indicator. If necessary add or subtract shims; or turn nut to get the correct end play.

Hub Nut Installation

1. Tighten the hub nut to a torque of 30 lb. ft. (40 N·m)

2. Tighten the nut more according to the chart.

Flywheel And Flywheel Housing Alignment

At the time of installation, check the flywheel and flywheel housing face and bore run out.

Instruments And Gauges

Oil Pressure Sending Units


SENDING UNIT FOR OIL PRESSURE
1. Terminal. 2. Fitting.

1. Connect the sending unit to a pressure source that can be measured with accuracy.

2. Connect an ohmmeter between fitting (2) and terminal (1).

3. Take resistance readings at the pressure shown in the chart.

4. If a unit does not have the correct resistance readings make a replacement of the unit.

Water Temperature Sending Unit

1. Connect an ohmmeter between terminal (1) and nut (2). Put bulb (3) in a pan of water. Do not let the bulb have contact with the pan.


SENDING UNIT FOR WATER TEMPERATURE
1. Terminal. 2. Nut. 3. Bulb.

2. Put a thermometer in the water to measure the temperature.

3. Take resistance readings at the temperatures shown in the chart.

4. If a unit does not have the correct resistance readings make a replacement of the unit.

Electric Gauges

1. Put the gauge in position with the letters horizontal and the face 30° back from vertical.


WIRING DIAGRAM FOR TEST
1. Terminal (for test voltage). 2. Test resistance.

2. Connect the gauge in series with the power source and the middle test resistance shown in the chart.

3. Let the gauge heat at the middle resistance for 5 minutes, then check the pointer position for all of the resistances given.

Mechanical Gauges For Temperature

Two types of mechanical gauges are available. The first type has a direct reading face. The second type has color codes on the face to show different ranges of operation. White, green and red show the cold, normal and hot ranges respectively.

To check both types of gauges, put the bulb of the gauge in a pan of oil. Do not let the bulb touch the pan. Put a thermometer in the oil to measure the temperature. Make a comparison of temperatures on the direct reading gauge or with temperature as shown on the chart for gauges with color codes.


DIRECT READING GAUGE


GAUGE WITH COLOR CODE

Mechanical Gauges For Oil Pressure

Two types of mechanical gauges are available. The first type has a direct reading face. The second type has color codes on the face to show different ranges of operation. Red, white and green show the low pressure, pressure at low idle rpm and normal pressure at low idle rpm and normal pressure ranges respectively. Some of the direct reading gauges are for gear oil pressure.

NOTE: Some gauges with color codes have only two ranges. Red for low pressure and green for normal pressure.

To check both types of gauges connect the gauge to a pressure source that can be measured with accuracy. Make a comparison of pressures on the gauge of test equipment with the pressures on the direct reading gauge or with the pressures as shown on the chart for gauges with color codes.


GAUGE WITH COLOR CODE


GAUGE WITH COLOR CODE


DIRECT READING GAUGE

Caterpillar Information System:

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