Engine

Engine hard to start, will not start.

Water, dirt or air in fuel system.

Drain, flush, fill and bleed fuel system.

Safety switches not activated.

Position levers in neutral.

Safety switches not adjusted.

Adjust correctly.

Safety switches faulty.

Replace switch.

Low compression.

Have John Deere serviceman check.

Low battery output.

Check electrolyte level and specific gravity of conventional battery. Charge, if necessary.

Excessive resistance in starting circuit.

Clean and tighten all connections on battery and starter.

Crankcase oil of too heavy viscosity.

Drain and fill crankcase with John Deere PLUS-50 ® oil of proper viscosity and quality.

Use of gasoline instead of diesel fuel, improper type or old fuel.

Consult fuel chart and use proper type of fuel for operating conditions.

Sticking valves.

See your John Deere dealer.

Throttle linkage loose or not adjusted properly.

Check throttle linkage and adjust, if necessary.

Fuel pump primer lever position.

Place lever in down position.

Solenoid disconnected.

Check wiring.

Dirty or faulty injectors

See your John Deere dealer.

Faulty injection pump solenoid.

Replace solenoid.

Plugged fuel filter.

Replace filter.

Three amp fuse left in diagnostic fuse location.

Remove

PLUS-50 is a trademark of Deere & Company.

NXC8,M64670,N5 -19-13FEB98-1/6

Engine knocks.

Low coolant temperature.

Incorrect or damaged thermostat.

Loose or failed main bearings, or connecting rod bearings. Worn pistons and cylinders.

See your John Deere dealer.

Insufficient oil.

Add oil of proper viscosity and quality.

Clogged air intake.

Clean air intake.

Injection pump out of time.

See your John Deere dealer.

Injection nozzle valve sticking

See your John Deere dealer.

Air in fuel system.

Clean and bleed fuel system.

Engine runs irregularly or stalls frequently.

Low coolant temperature.

Run engine until sufficiently warm, also check thermostat.

Clogged fuel filters or strainers.

Replace filter elements and bleed system. Clean strainers.

Bent pushrods or sticky valves.

See your John Deere dealer.

Water, dirt, or air in fuel system.

Drain, flush, fill, and bleed system. Tighten fuel connections.

Injection pump out of time.

See your John Deere dealer.

Injection pump speed advance.

See your John Deere dealer.

Dirty or faulty injectors.

See your John Deere dealer.

Solenoid wire loose.

Check wiring.

Low fuel level.

Add fuel and check system.

NXC8,M64670,N5 -19-13FEB98-2/6

Lack of power.

Engine overloaded.

Reduce load or shift to lower gear.

Intake air restrictions.

Replace air filter.

Improper thermostats.

Change to proper thermostats.

Improper valve clearance.

See your John Deere dealer.

High altitude operation.

Engine loses horsepower with increases in altitude. Use proper type of fuel for high altitude.

Unsatisfactory fuel.

Use correct fuel.

Overheated engine.

See "Engine overheats."

Throttle position or speed adjustments.

Use proper throttle position and speed adjustment.

Plugged or restricted fuel vents.

Clean fuel tank.

Fuel filters plugged.

Replace filter elements and bleed system.

Dirty or faulty injectors.

See your John Deere dealer.

Injection pump out of time.

See your John Deere dealer.

Automatic advance not working.

See your John Deere dealer.

NXC8,M64670,N5 -19-13FEB98-3/6

Engine overheats.

Engine overloaded.

Shift to lower gear or reduce load.

Low coolant level.

Fill radiator with coolant to proper level. Check hoses and radiator for leaks or loose connections.

Leaking head gaskets.

Tighten cap screws or replace gasket.

Engine out of time.

Check timing.

Dirty cooling system radiator core or screen.

Remove all foreign matter from exterior or radiator core and screen. Steam clean periodically.

Damaged thermostats, pressure cap, or gauge.

Remove and check.

Loose or defective fan belts.

Replace worn belts.

Wrong oil viscosity.

Change to proper oil viscosity.

Cooling system limed up.

Drain and flush cooling system.

Engine temperature below normal.

Damaged thermostats, gauge or sender units.

Remove and check.

Low oil pressure.

Low oil level.

Check crankcase oil level on dipstick and add oil, if necessary.

Improper type of oil.

Drain and fill crankcase with John Deere PLUS-50 ® oil of proper viscosity and quality.

PLUS-50 is a trademark of Deere & Company.

NXC8,M64670,N5 -19-13FEB98-4/6

Engine uses too much oil.

Oil leaks or engine overheating.

Check for leaks in lines and around gaskets and drain plugs.

Too low viscosity.

Drain and fill crankcase with oil of proper viscosity and quality.

Excessive engine speed.

Check speed adjustment.

High oil pressure.

See your John Deere dealer.

Scored pistons, stuck rings or worn valve guides.

See your John Deere dealer.

Internal parts worn.

See your John Deere dealer.

Restricted air intake system.

Check air cleaner and swab out air intake.

Crankcase breather plugged.

Unplug or unlink hose.

Engine uses too much fuel.

Improper type of fuel.

Use proper type fuel for operating conditions.

Engine out of time.

See your John Deere dealer.

Clogged or dirty air cleaner.

Clean air cleaner.

Engine overloaded.

Reduce load or shift to lower gear.

Dirty or faulty injectors.

See your John Deere dealer.

Engine emits black or gray exhaust smoke.

Improper type fuel.

Use proper type of fuel for operating conditions.

Engine out of time.

See your John Deere dealer.

Clogged or dirty air cleaner.

Check air cleaner for restrictions. Be sure filter element is clean.

Engine overloaded.

Reduce load or shift to lower gear.

Dirty or faulty injectors.

See your John Deere dealer.

Air in fuel system.

Bleed fuel system. Check all connections and fuel tank level.

NXC8,M64670,N5 -19-13FEB98-5/6

Engine emits white exhaust smoke.

Cold engine.

Warm engine to normal operating temperatures.

Engine out of time.

See your John Deere dealer.

Improper type of fuel.

Low octane fuel will cause misfiring. Use fuel which has recommended cetane or octane number.

Thermostats damaged or too cold.

Remove and check thermostat.

Battery will not charge.

Sulfated or worn out battery.

Check specific gravity and electrolyte level, if conventional battery.

Loose or damaged alternator.

Adjust belts. Replace if worn out.

Loose or corroded connections.

Clean and tighten battery connections.

Alternator or voltage regulator not functioning properly.

See your John Deere dealer.

Starter cranks slowly or will not crank.

Low battery output.

Check specific gravity and electrolyte level of battery.

Safety switch not activated.

Position hydrostatic speed range lever in neutral.

Loose or corroded harness or battery connections.

Clean and tighten loose connections.

Poor battery ground.

Clean contact surfaces.

Poor starter ground.

Clean contact surfaces.

Starter solenoid damaged.

Repair or replace, if necessary.

Cold weather.

See "Cold Weather Operation."

Circuit breaker damaged.

Replace circuit breaker.

Engine will not stop or "runs on."

Faulty fuel solenoid.

Replace fuel solenoid.

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