Doosan 9/235HA Operation & Maintenance Manual page 35

Unstable engine running.
Engine overheat.
Low oil pressure.
ENGINE INSTRUCTION MANUAL
Unstable low idling.
Incorrect high idle speed
adjustment.
Engine hunting in medium speed
range.
Engine malfunction in high speed
range.
Engine speed stuck at high idle.
Cooling system defect.
Improper servicing.
Lack of oil.
Wrong oil.
High coolant temperature.
Clogged filter and strainer.
Worn bearings and oil pump.
Faulty relief valve.
Crack in injection pipe.
Injection nozzle failure.
Engine stop solenoid return failure.
Uneven compression pressure between cylinders.
Incorrect control lever adjustment.
Governor internal malfunction.
Governor spring deteriorated.
Insufficient fuel supply.
Uneven fuel injection amount between cylinders.
Deteriorated governor spring.
Incorrect valve clearance adjustment.
Deteriorated valve spring.
Engine control restriction or seizure.
Insufficient coolant volume.
Fan belt slippage.
Thermostat malfunction.
Radiator filler cap malfunction.
Cooling system interior fouled.
Radiator clogged.
Engine over-loaded.
Air cleaner element clogged.
Insufficient airflow/restriction.
Restricted coolant flow (high concentration of antifreeze, etc.)
Oil leakage.
High oil consumption.
Wrong type and viscocity.
Over heat.
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Air in the fuel system.
Clogged fuel filter element.
Piping failure (squeezed/
restricted etc.).
9/235HA, 10/215HA