SECTION 6
LYCOMING OPERATOR’S MANUAL
TROUBLE-SHOOTING
O-360 AND ASSOCIATED MODELS
TROUBLE
PROBABLE CAUSE
REMEDY
Critical Altitude Lower Than
Exhaust bypass valve sticking
Clean and free action.
Specified (Cont.)
Engine Surges or Smokes
Air in oil lines or actuator
Bleed system.
Controller metering valve stem
Replace controller.
seal leaking oil into manifold
Clogged breather
Checkbreather for restrictions
to air flow.
NOTE
Smoke would be normal if engine has idled for a prolonged period.
High DeckPressure (Compressor
Controller metering valve not
Replace controller assembly or
Discharge Pressure)
opening, aneroid bellows leaking
replace aneroid bellows.
Exhaust bypass sticking closed
Shut off valve in return line not
working.
Butterfly shaft binding. Check
bearings.
Replace bypass valve or correct
linkage binding.
Controller return line restricted
Clean or replace line.
Oil pressure too high
Checkpressure 75 to 85 psi (80
psi desired) at exhaust bypass
actuator desired.
If pressure on outlet side of
actuator is too high, have
exhaust bypass controller
adjusted.
Exhaust bypass actuator piston
Remove and disassemble
locked in full closed position.
actuator, checkcondition of
(Usually accompanied by oil
piston and packing or replace
leakage at actuator drain line.)
actuator assembly.
NOTE:Exhaust bypass normally
closed in idle and low power
condition. Should open when
actuator inlet line is disconnected.
Exhaust bypass controller
Replace controller.
malfunction
6-6
