Atlas Copco QAS 14 Instruction Manual page 51

Black exhaust smoke
– Restriction in air filter/cleaner or induction
system.
– Fault in atomisers or atomisers of an incorrect
type.
– Fault in cold start system.
– Wrong type or grade of fuel used.
– Restriction in exhaust pipe.
– Engine temperature is too low.
– Incorrect valve tip clearances.
– Engine overload.
Blue or white exhaust smoke
– Wrong grade of lubricating oil.
– Fault in cold start system.
– Engine temperature is too low.
The engine knocks
– Fault in fuel lift pump.
– Fault in atomisers or atomisers of an incorrect
type.
– Fault in cold start system.
– Wrong type or grade of fuel used.
– Engine temperature is too high.
– Incorrect valve tip clearances.
The engine runs erratically
– Fault in fuel control.
– Restriction in a fuel pipe.
– Fault in fuel lift pump.
– Dirty fuel filter element.
– Restriction in air filter/cleaner or induction
system.
– Air in fuel system.
– Fault in atomisers or atomisers of an incorrect
type.
– Fault in cold start system.
– Restriction in fuel tank vent.
– Restricted movement of engine speed control.
– Engine temperature is too high.
– Incorrect valve tip clearances.
Vibration
– Fault in atomisers or atomisers of an incorrect
type.
– Restricted movement of engine speed control.
– Engine temperature is too high.
– Fan damaged.
– Fault in engine mounting or flywheel housing.
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The pressure of the lubricating oil is
too high
– Wrong grade of lubricating oil.
– Defective gauge.
The engine temperature is too high
– Restriction in air filter/cleaner or induction
system.
– Fault in atomisers or atomisers of an incorrect
type.
– Fault in cold start system.
– Restriction in exhaust pipe.
– Fan damaged.
– Too much lubricating oil in sump.
– Restriction in air or coolant passages of radiator.
– Insufficient coolant in system.
Crankcase pressure
– Restriction in breather pipe.
– Vacuum pipe leaks or fault in exhauster.
Bad compression
– Restriction in air filter/cleaner or induction
system.
– Incorrect valve tip clearances.