Failure Of Engine To Start; Failure Of Engine To Idle Properly - Lycoming O-290 Operator's Manual

LYCOMING OPERATOR'S MANUAL
O-235 AND O-290 SERIES
General – Experience has proven the best method of "trouble-shooting" is to decide on the various possible
causes of a given trouble and then to eliminate these causes one by one, beginning with the most probable.
The following chart lists some of the more common engine troubles usually found in maintaining aircraft
engines.
TROUBLE

Failure of Engine to Start

Failure of Engine to Idle Properly

SECTION 6
TROUBLE-SHOOTING
PROBABLE CAUSE
Lack of fuel.
Underpriming.
Overpriming.
Incorrect throttle setting.
Defective spark plugs.
Defective battery.
Improper operation of magneto
breaker points.
Water in carburetor.
Internal failure.
Incorrect carburetor idle
adjustment.
Idle mixture.
Leak in the induction system.
Low cylinder compression.
Insufficient spark.
TROUBLE-SHOOTING
REMEDY
Check fuel system for leaks. Fill
fuel tank. Clean dirty lines,
strainers or fuel cocks.
Prime with engine priming
system.
Open throttle and "unload"
engine.
Set at ¼ position.
Clean and adjust or replace spark
plug or plugs.
Replace with charged battery.
Clean points. Check internal
timing of magnetos.
Drain carburetor and fuel lines.
Check oil sump strainer for metal
particles. If found, complete
overhaul of engine is indicated.
Adjust throttle stop to obtain
correct idle.
Adjust mixture.
Tighten all connections in
induction system. Replace any
parts that are defective.
Check condition of piston rings,
and valves.
Check entire ignition system.
SECTION 6
6-1