IRONREFERENCE
ServiceSpecificationsTroubleshooting

Troubleshooting

MF 135 Engine Diagnostic Guide

Factory diagnostic reference for diesel and gasoline engines. Symptoms and probable causes extracted directly from the original operator's manual.

Source: MF 135 Operator's Manual (Form 1448 077 M6), pp. 57–60

Diesel Engine

Engine Cranking Failure4 causes
  1. 1Dual range shift lever not in "neutral" position.
  2. 2Loose, grounded, shorted or broken wiring. Check connections on all switches.
  3. 3Discharged or weak battery.
  4. 4Inoperative starting motor.
Engine Cranks but Fails to Start — Fuel System7 causes
  1. 1Lack of fuel in the tank. Fill tank and "air-bleed" the system.
  2. 2Excessive air in the fuel system. "Air-bleed" the entire fuel system.
  3. 3Fuel shut-off control rod in the "off" position.
  4. 4Fuel filters "clogged". Replace filter and "air-bleed" the system.
  5. 5Faulty injector assembly. Have your MF Dealer test, service or replace the assembly.
  6. 6Injection pump failure. Have your MF Dealer check the pump.
  7. 7Injection timing incorrect. Have your MF Dealer correctly time the pump.
Engine Cranks but Fails to Start — Air System2 causes
  1. 1Air cleaner inlet tube restricted.
  2. 2Plugged or "clogged" air cleaner.
Engine Operation Rough3 causes
  1. 1Injection pump incorrectly timed.
  2. 2Faulty injectors.
  3. 3Faulty injection pump.
Excessive Engine Exhaust Smoke6 causes
  1. 1Faulty injectors.
  2. 2Incorrect injection pump timing.
  3. 3Clogged air cleaner.
  4. 4Improper valve adjustment.
  5. 5Burned, worn or sticking valves.
  6. 6Excessive operation at low engine speeds.
Injection Pump Maximum Speed Incorrect2 causes
  1. 1Throttle linkage damaged. Replace and adjust linkage.
  2. 2Faulty injection pump governor. Have your MF Dealer check the pump.
Injection Pump Idle Speed Incorrect2 causes
  1. 1Idle speed stop screw adjusted incorrectly. Reset stop screw to 725–775 rpm.
  2. 2Improper pump timing. Have your MF Dealer time your injection pump.
Loss of Power10 causes
  1. 1Plugged fuel filter.
  2. 2Worn rings, pistons or sleeves, burned or sticking valves.
  3. 3Faulty injection pump governor linkage.
  4. 4Faulty throttle or governor linkage.
  5. 5Blown head gasket.
  6. 6Brakes dragging.
  7. 7Improper valve adjustment.
  8. 8Clogged air cleaner.
  9. 9Fuel shut-off rod linkage incorrect.
  10. 10Faulty pump timing.
Excessive Fuel Consumption12 causes
  1. 1Faulty injectors.
  2. 2Pump timing incorrect.
  3. 3Fuel pressure line leakage.
  4. 4Burned, worn or sticking valves.
  5. 5Worn pistons, rings or sleeves.
  6. 6Improper valve adjustment, worn or bent push rods.
  7. 7Engine overheating.
  8. 8Clutch slippage.
  9. 9Brakes dragging.
  10. 10Excessive exhaust back-pressure.
  11. 11Faulty cooling system thermostat.
  12. 12Clogged air cleaner or air pipe.
Erratic Misfire6 causes
  1. 1Faulty injectors.
  2. 2Weak or broken valve springs.
  3. 3Sticky valves.
  4. 4Excessive air in system.
  5. 5Plugged fuel filter.
  6. 6Water in fuel.
Engine Will Not Stop2 causes
  1. 1Fuel shut-off rod linkage incorrect. Readjust linkage.
  2. 2Improper pump functioning. Have your MF Dealer check.
Engine Knock2 causes
  1. 1Faulty injectors.
  2. 2Timing advanced. Have your MF Dealer correctly time the injection pump.

Gasoline Engine

Engine Cranking Failure4 causes
  1. 1Dual range shift lever not in "neutral" position.
  2. 2Loose, grounded, shorted or broken wiring. Check connections on all switches, solenoid, starting motor and battery.
  3. 3Discharged battery.
  4. 4Inoperative starting motor.
Engine Cranks but Will Not Start — Ignition Spark Failure4 causes
  1. 1Loose, grounded, shorted or broken ignition wiring. Check connections on ignition switch, ammeter, coil, distributor and spark plugs.
  2. 2Mechanical failure of spark plugs — cracked or broken porcelain, incorrect gap setting, electrodes fouled.
  3. 3Distributor failure. Inspect cap for cracks, carbon traces and condition of wire terminals. Wipe clean of dirt and moisture. Inspect rotor, breaker points, condenser and wiring connections.
  4. 4Faulty coil. Remove high tension wire from center of distributor and hold end of wire about 1/4" from suitable ground. With ignition switch "on", crank engine and note if coil produces spark — should be a strong blue spark, not a weak yellow one. If no spark occurs, check all primary wiring before condemning coil.
Engine Cranks but Will Not Start — Carburetion Failure15 causes
  1. 1Choke not pulled out when engine is cold.
  2. 2Throttle closed.
  3. 3Fuel shut-off valve not open.
  4. 4Fuel tank empty.
  5. 5Clogged vent in fuel cap.
  6. 6Clogged fuel filter or screens.
  7. 7Restricted fuel line.
  8. 8Restricted carburetor passages.
  9. 9Water deposited in carburetor. In cold temperatures, water freezing would prevent gasoline flow.
  10. 10Air cleaner inlet tube restricted.
  11. 11Clogged air cleaner.
  12. 12Throttle and/or governor linkage inoperative or incorrectly adjusted.
  13. 13Air leak in fuel line.
  14. 14Cracked or broken intake manifold.
  15. 15Valves sticking.
Engine Cranks Slowly3 causes
  1. 1Weak battery.
  2. 2Crankcase oil too heavy for temperature.
  3. 3Defective starter or connections.
Excessive Fuel Consumption15 causes
  1. 1Fuel leak.
  2. 2Fouled air cleaner.
  3. 3Timing off.
  4. 4Automatic spark advance not working properly.
  5. 5Distributor points need replacing.
  6. 6Spark plugs need servicing or replacing.
  7. 7Faulty wiring.
  8. 8Improper valve timing.
  9. 9Burned, worn or sticking valves.
  10. 10Worn pistons, rings or sleeves.
  11. 11Improper valve adjustment, worn or bent push rods.
  12. 12Engine overheating.
  13. 13Clutch slipping.
  14. 14Brakes dragging.
  15. 15Excessive exhaust back pressure.
Excessive Oil Consumption9 causes
  1. 1Oil leak.
  2. 2Plugged breather pipe.
  3. 3Worn valve guides.
  4. 4Worn, broken or ill-fitted rings.
  5. 5Worn, scored or out-of-round cylinders or pistons.
  6. 6Worn ring grooves.
  7. 7Inverted rings.
  8. 8Stuck piston rings.
  9. 9Worn neoprene oil guard gaskets on the intake valves.
Loss of Power11 causes
  1. 1Dirty carburetor.
  2. 2Faulty ignition.
  3. 3Worn rings, pistons, or sleeves; burned or sticking valves.
  4. 4Faulty governor operation.
  5. 5Faulty throttle, governor or choke linkage.
  6. 6Crack in intake manifold or leaky gasket.
  7. 7Blown head gasket.
  8. 8Brakes dragging.
  9. 9Improper valve adjustment, worn or bent push rods.
  10. 10Excessive exhaust back-pressure.
  11. 11Clogged air cleaner.
Erratic Misfire4 causes
  1. 1Dirty carburetor.
  2. 2Weak or broken valve springs.
  3. 3Sticking valves.
  4. 4Faulty ignition.
Pre-Ignition8 causes
  1. 1Poor grade of fuel.
  2. 2Ignition timing too far advanced.
  3. 3Engine overheating.
  4. 4Heavy carbon deposits in the combustion chamber.
  5. 5Spark plugs of improper heat range.
  6. 6Insufficient tappet clearance.
  7. 7Burned or worn valves.
  8. 8Improper distributor advance.
Continuous Misfire4 causes
  1. 1Stuck or burned valves.
  2. 2Blown head gasket.
  3. 3Faulty ignition.
  4. 4Improper timing.
Engine Overheating8 causes
  1. 1Thermostat stuck closed.
  2. 2Water leakage — too low water level.
  3. 3Fan belt slipping.
  4. 4Clogged radiator core.
  5. 5Carburetor mixture too lean.
  6. 6Improper ignition timing.
  7. 7Fouled cooling system.
  8. 8Improper valve timing.

Related Reference

This troubleshooting guide is extracted verbatim from the factory operator's manual. For repairs beyond routine adjustment, consult a qualified Massey-Ferguson dealer.