SUPPLEMENT FOR 3116 & 3126 MARINE ENGINE Caterpillar


Testing & Adjusting

Usage:

Introduction

When the words "use again" are in the description, the specification given can be used to determine if a part can be used again. If the part is equal to or within the specification given, use the part again.

When the word "permissible" is in the description, the specification given is the "maximum or minimum" tolerance permitted before adjustment, repair and/or new parts are needed.

A comparison can be made between the measurements of a worn part and the specifications of a new part to find the amount of wear. A part that is worn can be safe to use if an estimate of the remainder of its service life is good. If a short service life is expected, replace the part.

Troubleshooting (Indicators, Controls & Air Inlet Heater)

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 correction 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 cannot give all possible problems and corrections. The service technician must find the problem and its source, then make the necessary repairs.

NOTE: For each problem, a list of possible causes and corrections is given. The list of probable causes and corrections should be performed in numeric sequence.

1. Contactor Switch For Water Temperature Does Not Activate Alarm.
2. Contactor Switch For Water Temperature Activates At Wrong Temperature.
3. Contactor Switch For Oil Pressure Does Not Activate Alarm.
4. Electrical Indicators Give Wrong Readings.
5. Air Inlet Heater.

Troubleshooting Problems

Problem 1: Contactor Switch For Water Temperature Does Not Activate Alarm.

Probable Cause:

* Wrong Connections
* Failure Of Alarm
* Low Water Level In Cooling System
* Wrong Setting Of Switch
1. Wrong Connections:

Check connections and wiring. Correct where necessary.

2. Failure Of Alarm:

Check alarm for proper operation.

3. Low Water Level In Cooling System:

Fill the cooling system.

4. Wrong Setting Of Switch:

Make a test of temperature setting and if necessary install new contactor switch with correct setting. See specifications.

Problem 2: Contactor Switch For Water Temperature Activates At Wrong Temperature.

Probable Cause:

* Wrong Setting Of Switch
1. Wrong Setting Of Switch:

Make a test of temperature setting and if necessary install new contactor switch with correct setting. See specifications.

Problem 3: Contactor Switch For Oil Pressure Does Not Activate Alarm.

Probable Cause:

* Wrong Connections
* Failure Of Alarm
* Wrong Setting Of Switch
1. Wrong Connections:

Check connections and wiring. Correct where necessary.

2. Failure Of Alarm:

Check alarm for proper operation.

3. Wrong Setting Of Switch:

Make a test of temperature setting and if necessary install new contactor switch with correct setting. See specifications.

Problem 4: Electrical Indicators Give Wrong Readings.

Probable Cause:

* Wrong Connections
* Sending Units Have A Failure
* Wrong Sending Unit In System
* Wrong Indicator
1. Wrong Connections:

Check connections and wiring. Correct where necessary.

2. Sending Units Have A Failure:

Check the sending units and install new ones if necessary.

3. Wrong Sending Unit In System:

Install correct sending unit.

4. Wrong Indicator:

Install correct indicator.

Problem 5: Air Inlet Heater:

Probable Cause:

* Heater Stays On Longer Than Allotted Time - Any Cycle
* Heater Does Not Come On
* System Check

Lamp Test

Pre-Heat Cycle

Crank Heat Cycle

Regular Heat/Run Cycle

Heater Element Check

Coolant Sensor Check

Oil Pressure Switch Check

Probable Cause:

1. Heater Stays On Longer Than Allotted Time-Any Cycle:

Replace the air inlet heater control module. Note: Cycle times are approximate only. Some variance does not necessarily indicate a system failure.

2. Heater Does Not Come On:

Check for the following:

* a defective heater control module.
* a defective oil pressure switch (regular heat cycle only).
* a defective coolant sensor.
* a defective heater element.
* a defective power relay (magnetic switch).
* a poor connection or damaged wire

------ WARNING! ------

To avoid personal injury (burns), make sure the coolant temperature is below 38°C (100°F) before performing any tests.

--------WARNING!------
3. System Check:

NOTE: The procedures that follow are step-by-step diagnostic checks that must be performed in sequence. Failure to do so may result in incorrect diagnosis and unnecessary expense.

3(A). Lamp Test:

a. Inspect the lamp, replace if necessary.

b. Check lamp wiring harness for a cut/broken wire or poor connection.

c. If after inspecting the lamp and harness the lamp still does not illuminate proceed with the cycle tests that follow.

NOTE: If the coolant temperature is below 35 ± 4°C (95 ± 7°F), the system should go directly from the lamp test into the pre-heat cycle (light will not turn off).

3(B). Pre-Heat Cycle:

With the help of a co-worker, turn the key switch to the "ON" position or the ignition switch to the "RUN" position and feel the power relay (magnetic switch) for a "click", indicating the relay is energized. The air inlet heater magnetic switch will normally be located inside the junction box. If no click is felt when the switch is turned to the "RUN" position, proceed as follows:

NOTE: It may be necessary to reset the ignition switch (turn off then back on), periodically while preforming these diagnostic checks. The pre-heat cycle times out in thirty seconds and any tests performed after that period will lead to an incorrect diagnosis.

a. Disconnect the electrical connector at the control module. Attach a voltmeter between terminal "F" and terminal "A" on the module plug portion of the wiring harness.

b. With the ignition in the "RUN" or key switch "ON" position, a reading of 12 or 24 volts should be evident.

c. If no reading is noted, inspect the vehicle's wiring system for a blown fuse, cut/broken wire or a poor connection. Check both the power (terminal "F" and ground (terminal "A") wires.

d. If a reading of 12 or 24 volts is noted, reconnect the connector.

e. Disconnect the wiring harness at the coolant sensor. With a small "jumper" wire, connect the two (2) terminals on the module end of the wiring harness.

f. With the help of a co-worker, turn the ignition switch to the "RUN" or the key switch "ON" position and feel the power relay (magnetic switch) for a "click", indicating the relay is energized.

g. If the click is felt, the coolant sensor has not reset to the closed position due to the coolant temperature not reaching 35°C (95°F) or below or the coolant sensor is defective. Perform the Coolant Sensor Check and replace the coolant sensor if necessary.

h. If a click is not felt with the coolant sensor leads jumped, attach a test light at the power relay (magnetic switch). Power should be present at both terminals on the coil side of the relay.

1. If power is present on the module side but not on the heater side of the relay, replace the relay.

2. If power is present on both sides of the relay, remove the ground lead from the relay. (The ground wire attaches to terminal "D" of the control module). Ground the relay to the starting motor or battery. If the relay energizes, the control module is defective and must be replaced.

i. If the power relay (magnetic switch) energizes, yet the heater does not operate, use a test light to check for power on the contact side of the relay. Lack of power indicates a wiring problem. Check the vehicle's harness for a cut/broken wire or a poor connection.

j. If power is present on the heater side of the relay and the heater is still not operating, inspect the heater ground wires. If there are no defects, perform the Heater Element Check.

3(C). Crank Heat Cycle:

If the heater does not come on when the engine is being cranked, proceed as follows:

A. Follow Steps a-j of the 3(B) Pre-Heat Cycle Test. If the system operation is correct to this point, allow the heater to remain in pre-heat mode until it times out (30 seconds). Feel the power relay (magnetic switch) for a second click as the heater is deactivated. If the relay does not click a second time or stays on longer than 30 seconds, replace the control module.

B. After the 30 second period the heater should be deactivated. With the help of a co-worker, turn the ignition switch from the "RUN" position to the "START" position or push the "START" switch and feel the power relay (magnetic switch) for a click. If none is present proceed as follows:

a. Disconnect the electrical connector at the control module. Attach a voltmeter between terminal "B" and terminal "A" on the module plug portion of the wiring harness.

b. With the ignition in the "START" position or the "START" button pressed a reading of 12 volts (or 24 V) should be present.

c. If no reading is noted, inspect the wiring system for a blown fuse, cut/broken wire or a poor connection. Check both the power (terminal "B") and ground (terminal "A") wires.

d. If a reading of 12 or 24 volts is noted, replace the control module.

NOTE: The heater should continue to operate for a maximum of thirty seconds after the ignition is released from the "START" position if the engine is not operating. If the heater does not operate or operates for longer than thirty seconds, replace the control module.

3(D). Regular Heat/Run Cycle:

If the heater does not come on when the engine is started and is running, proceed as follows:

a. Follow Steps a-j of the 3(B) Pre-Heat Cycle Test with the only exception being that the engine is started and running. If the system does not function with the coolant sensor jumped, proceed as follows:

b. Leave the coolant sensor leads jumped.

c. Disconnect the wiring harness at the oil pressure switch. Using a voltmeter, check for power on the oil pressure switch plug portion of the wiring harness.

d. Inspect the wiring harness for a blown fuse, cut/broken wire or a poor connection if no power is present.

e. If a reading of 12 or 24 volts is noted, connect the two oil pressure switch terminals on the oil pressure switch plug portion of the wiring harness with a small "jumper" wire.

f. With the help of a co-worker, start the engine and feel for the click in the power relay (magnetic switch).

g. If the relay clicks, replace the oil pressure switch.

NOTE: Before replacing the oil pressure switch make certain the oil pressure at the oil manifold is greater than 241 ± 69 kPa (35 ± 10 psi) with the engine running.

h. If the coolant sensor and pressure switch are both jumped and the power relay (magnetic switch) does not click, then the control module may be defective.

3(E). Heater Element Check:

If, during the inspection of the controller, no malfunction can be found and the heater still does not operate, the heater element may be defective. Inspect the heater element as follows:

Using an ohmmeter, measure the resistance across the front and rear terminals of the heater. There should be very little resistance to the current flow.

a. If the meter reads an infinite resistance, the heater element is defective and should be replaced.

b. If the ohmmeter reads a very low resistance, check both ground wires from the heater to the starting motor.

3(F). Coolant Sensor Check

The coolant sensor used in the air inlet heater is designed to open at 49 ± 4°C (120 ± 7°F) and reset (close) at 35 ± 4°C (95 ± 7°F). To test the sensor proceed as follows:

a. Remove the sensor from the water temperature regulator housing and place in a container of cold water [10°C (50°F) or less].

b. Connect an ohmmeter across the leads of the sensor. After allowing the sensor temperature to equalize with the water temperature, make certain that the temperature is still near 10°C (50°F). The sensor should be closed at this point and offer very little resistance.

c. Place a thermometer in the container and heat the water slowly while stirring. At 49 ± 4°C (120 ± 7°F) the reading should change to infinite resistance (open switch).

d. Cool the water by slowly adding ice while stirring. When the water temperature reaches 35 ± 4°C (95 ± 7°F) the reading should change from infinite to minimal resistance.

e. If any of these conditions are not met, the sensor should be replaced.

3(G). Oil Pressure Switch Check:

The oil pressure switch used in the air inlet heater system is designed to be open below 241 ± 69 kPa (35 ± 10 psi) and closed above 241 ± 69 kPa (35 ± 10 psi). To test the oil pressure switch proceed as follows:

a. With the engine stopped, disconnect the lead to the oil pressure switch in the oil manifold.

b. Connect an ohmmeter across the oil pressure switch leads on the controller side of the wiring harness.

c. With the engine stopped [0 kPa (0 psi) oil pressure], the ohmmeter should read infinite resistance (open circuit).

d. Start the engine and increase the rpm until the oil pressure is 241 ± 69 kPa (35 ± 10 psi). At some point in this range, the resistance should go from infinity to zero (0) ohms (closed circuit).

e. If either of these conditions are not met, the oil pressure switch should be replaced.

Governor

Low Idle Adjustment Procedure

Use the 9U7400 Multitach Group or the 1U6602 Photo Tachometer to accurately measure the engine low idle rpm. DO NOT use the instrument panel tachometer to set engine low idle. Use this procedure any time the low idle rpm is changed, even slightly.


Governor (Typical)
(1) "Standard" low idle adjustment screw. (2) "Buffer" spring adjustment screw.

1. Start the engine and allow it to warm up to operating temperature and allow the low idle reading to stabilize. Low idle readings should be taken after snapping the throttle open about 1/3 of its travel, and releasing it quickly. This will help insure the governor control is in its natural low idle position against the "standard" low idle adjustment screw (1).

2. Turn the "buffer" spring adjustment screw (2) out (counterclockwise) until there is no further change in low idle rpm. The rpm should drop slightly when the "buffer" spring adjustment screw (2) is turned out.

2. Actuate the governor control lever, and then quickly release the lever. Check the low idle rpm. Use the "standard" low idle adjustment screw (1) to adjust the low idle to 690 rpm. Actuate the governor control lever, and then quickly release the lever. Check the low idle rpm. Adjust the "standard" low idle adjustment screw (1) as needed to obtain the 650 rpm.

4. Slowly turn the "buffer" spring adjustment screw (2) in (clockwise) until the low idle rpm begins to increase. Continue to turn the "buffer" spring adjustment screw (2) until the low idle rpm is 650 rpm. Actuate the governor control lever, and then quickly release the lever. Check the low idle rpm. Adjust the "buffer" spring adjustment screw (2) as needed to obtain the 650 rpm.

NOTE: The "buffer" spring adjustment screw (2) MUST be turned out (counterclockwise) initially, while the low idle is set 10 rpm LESS than the final value with the "standard" low idle adjustment screw (1). Then the "buffer" spring adjustment screw (2) is used to adjust the low idle rpm upward to the final, specified, low idle rpm. If the "buffer" spring adjustment screw (2) is used to raise the rpm too much or too little, it does not dampen the movement of the internal governor parts. Low idle instability or surge can be a result.

Instruments And Indicators

Contactor Switch For Water Temperature

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


Heat Sink [Dimensions in mm (in)]

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

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 multimeter 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. Stir the water while using a torch to heat it to the specified temperature given in specifications and check resistance. If the temperature contactor is not in specification a replacement must be made.

Water Temperature Sending Unit


Sending Unit For Water Temperature
(1) Bulb. (2) Nut. (3) Connection.

1. Connect a multimeter between terminal (3) and nut (2). Put bulb (1) in heat sink then into a pan of water. Do not let the bulb have contact with the pan (see contactor switch for more detail).

2. Put a 2F7112 Thermometer in the water to measure the temperature.

3. Refer to Water Temperature Sending Unit in the Specifications section. Take resistance readings at the temperature shown.

4. If a unit does not have the correct resistance readings, replace the unit.

Magnetic Pickup


Typical Illustration

(1) Clearance between magnetic pickup and flywheel ring gear ... 0.55 to 0.83 mm (.022 to .033 in)

NOTE: With the engine stopped, turn the pickup in until it comes in contact with the teeth on the flywheel ring gear. Turn the pickup out 1/2 turn. This will give 0.55 to 0.83 mm (.022 to .033 in) clearance.

(2) Tighten the locknut to a torque of ... 45 ± 7 N·m (33 ± 5 lb ft)

Tachometers

Tachometers can be adjusted by the following procedure.

1. Remove the plastic plug on the rear of the tachometer.

2. Using a small screw driver, turn the adjusting screw to increase or decrease the tachometer reading.

3. Replace the plastic cap.

Electric Indicators

1. Put the indicator in position with the letters horizontal and the face 30 degrees back from vertical.


Wiring Diagram For Test
(1) Terminal (for test voltage). (2) Test resistance.

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

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

NOTE: Refer to the indicator area in the Specifications section for the calibration information of each indicator.

Electric Starting Motor Adjustments

Solenoid Position Adjustment

3E6343, 4N7153 and 7T2266

The solenoid position on the starting motor controls pinion clearance. If the solenoid position is correct, the pinion clearance is correct. Do the following procedure to adjust the solenoid position.


Solenoid Assembly
(1) Intermediate housing. (2) Solenoid mounting bracket. (3) Bolts. (X) 62.50 + 0.20 - 0.50 mm (2.46 + .008 - .020 in).

1. Check distance (X) between intermediate housing (1) and solenoid mounting bracket (2) with calipers.

2. If distance (X) is not correct, loosen bolts (3) and move the solenoid until distance (X) is correct. Bracket (2) has elongated holes.

3. Tighten bolts (3) to 7 to 10 N·m (5 to 7 lb ft) after the adjustment is correct.

Pinion Clearance

8C4090, 3E1944, 3E7676, 3E7677, 3E8845, 9X3491, 104-5724 and 104-5725

When the solenoid is installed, make an adjustment of the pinion clearance. The adjustment can be made with the starting motor removed.


Connection For Checking Pinion Clearance
(1) Connector (from MOTOR terminal on solenoid to motor). (2) SW terminal. (3) Ground terminal.

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

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

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

4. Connect for a moment, a wire from the solenoid connection (terminal) marked MOTOR to the ground connection (terminal). The pinion will shift to crank position and will stay there until the battery is disconnected.


Pinion Clearance Adjustment
(4) Shaft nut. (5)) Pinion. (6) Pinion clearance.

5. Push the pinion toward the commutator end to remove free movement.

6. Pinion clearance (6) must be as stated for the starting motor in the Specifications section of this manual.

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

8. Install plug.

Power Take-Off Group (Front)


(1) Shaft. (2) Nameplate.

After the clutch has been assembled to the engine. Rap the shaft (1) sharply on the end to relieve any preloading that may result due to resistance of the pilot bearing being pressed into the drive coupling. Check for proper engagement force which is measured in torque on the splined shaft. Required torque is 119 to 158 N·m (27 to 36 lb) to engage clutch. Remove the nameplate (2) from the housing and turn the clutch shaft until adjusting lock pin can be reached. Disengage adjusting lock pin and turn adjusting ring clockwise to increase engagement torque and counterclockwise to decrease engagement torque. Replace nameplate (2) after adjustments are complete.

Caterpillar Information System:

SUPPLEMENT FOR 3116 & 3126 MARINE ENGINE Systems Operation
SUPPLEMENT FOR 3116 & 3126 MARINE ENGINE Power Take-Off Group (Front)
SUPPLEMENT FOR 3116 & 3126 MARINE ENGINE Auxiliary Water Pump
SUPPLEMENT FOR 3116 & 3126 MARINE ENGINE Jacket Water Heater
SUPPLEMENT FOR 3116 & 3126 MARINE ENGINE Water Temperature Regulator
SUPPLEMENT FOR 3116 & 3126 MARINE ENGINE Electric Starting Motor Solenoid
SUPPLEMENT FOR 3116 & 3126 MARINE ENGINE Electric Starting Motor
SUPPLEMENT FOR 3116 & 3126 MARINE ENGINE Regulator
SUPPLEMENT FOR 3116 & 3126 MARINE ENGINE Alternator
SUPPLEMENT FOR 3116 & 3126 MARINE ENGINE Sensors Low Coolant Level
SUPPLEMENT FOR 3116 & 3126 MARINE ENGINE Circuit Breaker
SUPPLEMENT FOR 3116 & 3126 MARINE ENGINE Magnetic Starter Switch Assembly
SUPPLEMENT FOR 3116 & 3126 MARINE ENGINE Alternator
SUPPLEMENT FOR 3116 & 3126 MARINE ENGINE Watercooled Turbocharger
SUPPLEMENT FOR 3116 & 3126 MARINE ENGINE Watercooled Turbocharger
SUPPLEMENT FOR 3116 & 3126 MARINE ENGINE Water Temperature Regulator Housing
SUPPLEMENT FOR 3116 & 3126 MARINE ENGINE Water Temperature Regulator Housing
SUPPLEMENT FOR 3116 & 3126 MARINE ENGINE Water Temperature Regulator
SUPPLEMENT FOR 3116 & 3126 MARINE ENGINE Expansion Tank
SUPPLEMENT FOR 3116 & 3126 MARINE ENGINE Heat Exchanger
SUPPLEMENT FOR 3116 & 3126 MARINE ENGINE Raw Water Pump
SUPPLEMENT FOR 3116 & 3126 MARINE ENGINE Oil Cooler (Marine Transmission Gear)
3406B INDUSTRIAL & MARINE ENGINES Introduction
3406B INDUSTRIAL & MARINE ENGINES Engine Design
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