Lycoming O-235 series, Operator'S Manual

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LYCOMING OPERATOR’S MANUAL SECTION 6
O-235 AND O-290 SERIES TROUBLE-SHOOTING
TROUBLE PROBABLE CAUSE REMEDY
Rough Engine Cracked engine mount. Replace mount.
Unbalanced propeller. Remove propeller and have it
checked for balance.
Defective mounting bushings. Install new mounting bushings.
Malfunctioning engine. Check entire engine.
Low Oil Pressure Insufficient oil. Fill sump to proper level with oil
of recommended grade.
Air lock or dirt in relief valve. Remove and clean oil pressure
relief valve.
Leak in suction line or pressure
line. Check gasket between accessory
housing and crankcase.
Dirty oil strainers. Remove and clean oil strainers.
High oil temperature. See “High Oil Temperature” in
“Trouble” column.
Defective pressure gage. Replace gage.
Stoppage – oil pump intake
passage. Check line for obstruction. Clean
suction strainer.
High Oil Temperature Insufficient air cooling. Check air inlet and outlet for
deformation or obstruction.
Insufficient oil supply. Fill oil sump to proper level with
oil of recommended grade.
Low grade of oil. Replace with oil conforming to
specification.
Clogged oil lines or strainers. Remove and clean oil strainers.
Excessive blow-by. Usually caused by worn or stuck
rings. Complete overhaul
required.
Failing or failed bearing. Examine sump for metal particles.
If found, complete overhaul of
engine is indicated.
Defective temperature gage. Replace gage.
6-3