695578
Table 1. 4-Cycle Engine Troubleshooting Chart
Engine Fails to Start or Starts with Difficulty
No fuel in tank.
Fill tank with clean, fresh fuel.
Shut-off valve closed.
Open valve.
Tank cap vent obstructed.
Clean the vent or replace the cap.
Obstructed fuel line.
Clean fuel screen and line. If necessary, remove and clean
carburetor.
Engine flooded.
Close fuel shut-off, if so equipped, and pull starter until engine
starts. Reopen fuel shut-off for normal fuel flow.
Water in fuel.
Drain tank. Clean carburetor and fuel lines. Dry spark plug
points. Fill tank with clean, fresh fuel.
Spark plug fouled.
Replace spark plug.
No spark at plug.
Check ignition air gap. If air gap is correct and there is no
spark at plug replace ignition.
Spark plug porcelain cracked.
Replace spark plug.
Electric starter does not crank engine.
See 12 volt starter troubleshooting chart.
Loose or defective ignition wiring.
Check ignition wiring for shorts or grounds; repair if necessary
Incorrect timing.
Flywheel key has sheared or partially sheared. Replace key.
Poor compression.
Overhaul engine.
Remedy and Reference
Cause
Chapter 13
Troubleshooting
The following charts can be helpful in locating the most common troubles associated with gasoline engines; Pos-
sible causes and remedies are listed below. Refer to the appropriate sections in this Technician's Handbook for
further detail of procedures.
Engine Knocks
13-1
Loose flywheel.
Check flywheel key and keyway; replace parts if necessary.
Tighten flywheel nut to proper torque.
Improper ignition timing.
Flywheel key has sheared or partially sheared. Replace
key.
Carbon in combustion chamber.
Remove cylinder head and clean carbon from head and
piston.
Loose or worn connecting rod.
Replace connecting rod.
Worn cylinder.
Replace cylinder.
