Cessna 150 Series Service Manual page 131

11-10. TROUBLE SHOOTING (Cont).
TROUBLE
PROBABLE CAUSE
REMEDY
HIGH CYLINDER HEAD Low grade of fuel. Drain and fill with correct grade
TEMPERATURE.
of fuel. Refer to Section 2.
Lean fuel-air mixture.
Refer to Owner's Manual for
correct leaning procedure.
Excessive carbon deposits in
Install new cylinders and piston
cylinder head and on pistons. rings or new engine.
Cylinder baffles loose or bent.
Check all baffles and correct.
Dirt between cylinder fins.
Clean thoroughly.
HIGH OIL TEMPERATURE.
Low oil supply.
Replenish.
Oil viscosity too high.
Refer to Section 2 for seasonal
grades.
Prolonged high speed operation
Hold ground running above 1500
on ground.
RPM to a minimum.
LOW OIL PRESSURE.
Low oil supply.
Replenish.
Oil viscosity too low.
Drain and refill with correct
seasonal grade. Refer to
Section 2.
Sludge or foreign material in
Remove and clean valve parts.
relief valve.
Foam in oil due to emulsification
Drain and refill with fresh oil.
of alkaline solids.
Refer to Section 2 for seasonal
grade.
Defective pressure gage.
Check with known good gage.
Replace defective gage.
Oil pump defective.
Remove and inspect.
Examine
engine. Metal particles from
damaged pump may have entered
engine oil passages.
Oil congealed in gage line.
Disconnect line at engine and gage;
flush with kerosene.
Pre-fill line
with kerosene and install.
Oil pressure line broken, dis-
Inspect, replace or connect
connected or pinched.
line.
Internal leak, burned bearings,
Major overhaul.
or damaged gasket.
Change 1 11-6A/( 1-6B blank)