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Kubota D650 Troubleshooting

Engine Model: Kubota D650
Engine Type: 4-cycle 3-cylinder liquid-cooled diesel engine
Total Displacement: 41.2 (0.68 cc)
Rated Engine Power: 14.3 Hp (11.2 kW) at 3200 rpm
Aspiration Type: Naturally aspirated


Engine hard to start or will not start

Fuel filter plugged - Install new filter element.
Air in the fuel pipes - Bleed the fuel pipes.
Faulty or dirty injection nozzles - Check and replace nozzles if required.
Fuel injection pump malfunction - Change pump or rebuild it.

Diesel starts and stops

Dirty fuel filter - Replace the filter element.
Fuel injection pump is broken - Install a new pump or rebuild.
Air filter is dirty - Clean or change the filter.

Diesel shuts off while driving

Fuel injection pump timing is wrong - Set it up as required.
Dirty fuel filter - Replace filter element.
Engine is not fully warmed up - Engine is not warmed up to the required temperature.

Engine stops at idle

Low idle speed setting is incorrect - Correct low idle settings.
Valve clearance is not correct - Have it adjusted.
Fuel injection pump is broken - Rebuild or change fuel pump.

Engine is not running at maximum power

Damaged or dirty injection nozzles - Replace injection nozzles.
Dirty fuel lines or hoses - Clean fuel system hoses and lines.
Air filter clogged - Service or replace the air filter.
Cylinder head gasket is defective - Gasket should be replaced.

Engine is overheated

Dirty radiator fins or faulty radiator cap - Clean radiator or change cap.
Low coolant level - Add coolant and check the components of cooling system.
Broken or loose fan belt - Replace the fan belt.
Engine oil level is insufficient - Checking oil level and add if necessary.

Oil pressure is insufficient

Engine oil insufficient - Add oil to the engine crankcase.
Defective oil pump - Repair or replace.
Oil filter is dirty - Clean or change engine oil filter.

Diesel engine consuming too much oil

Oil leakage: Gaskets or seals can be faulty - Replace defective parts.
Oil viscosity is incorrect - Fill up with the correct oil viscosity.
Piston rings are stuck or broken - Piston rings replacement required.
Worn valve stems and valve guides - Valves must be replaced.
Damaged cylinder liners or pistons - Inspect pistons and liners, fit new components as necessary.

Engine noise or knocking

Engine is not warmed up to the required temperature - Warm up the engine.
Lack of engine oil - Need to add engine oil.
Fuel injection pump timing is wrong - Adjust according to specifications.
Broken or worn pistons - Pistons replacement required.
Misaligned or faulty connecting rod - Need to align or replace the connecting rod.

Starter cranks slow

Low battery output - Battery is drained, charge it.
Battery will not hold charge - Service battery or replace it.
Terminals are faulty or battery cables are disconnected - Check wiring connections and replace or clean terminals.

Starter motor won't turn

Battery is drained or worn - Recharge or replace battery.
Battery cables are disconnected or incorrectly connected - Check cables and connect as needed.
Low battery capacity - Battery is drained, charge it.
Defective starter motor - Repair or change starter.