Doosan 7/26E, Operation And Maintenance Manual

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ENGINE TROUBLESHOOTING 79
7/26E, 7/31E, 7/41
Unstable engine running
Unstable low idling
Crack in injection pipe.
Injection nozzle failure.
Engine stop solenoid return failure.
Uneven compression pressure between cylinders.
Incorrect high idle speed
adjustment.
Incorrect control lever adjustment.
Governor internal malfunction.
Engine hunting in medium speed
range.
Governor spring deteriorated.
Engine malfunction in high speed
range.
Insufficient fuel supply.
Air in the fuel system
Clogged fuel filter element
Piping failure (squeezed/restricted
etc.)
Uneven fuel injection amount between cylinders.
Deteriorated governor spring.
Incorrect valve clearance adjustment.
Deteriorated valve spring.
Engine speed stuck at high idle. Engine control restriction or seizure.
Engine overheat.
Cooling system defect
Insufficient coolant volume.
Fan belt slippage.
Thermostat malfunction.
Radiator filler cap malfunction.
Cooling system interior fouled.
Radiator clogged.
Improper servicing
Engine over-loaded.
Air cleaner element clogged.
Insufficient airflow/restriction.
Restricted coolant flow (high concentration of antifreeze, etc.)
Low oil pressure
Lack of oil
Oil leakage
High oil consumption
Wrong oil Wrong type and viscosity.
High coolant temperature. Over heat.
Clogged filter and strainer.
Worn bearings and oil pump.
Faulty relief valve.