Chapter 13 Troubleshooting - Tecumseh VLV Technician's Handbook

B. 4-CYCLE ENGINE TROUBLESHOOTING CHART
Cause
ENGINE FAILS TO START OR STARTS WITH DIFFICULTY
No fuel in tank
Shut-off valve closed
Obstructed fuel line
Incorrect Timing
Tank cap vent obstructed
Water in fuel
Engine flooded
Loose or defective ignition wiring
Spark plug fouled
Spark plug porcelain cracked
Poor Compression
No spark at plug
Electric starter does not crank engine
ENGINE KNOCKS
Carbon in combustion chamber
Loose or worn connecting rod
Loose flywheel
Worn cylinder
Improper ignition timing
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Chapter 13
TROUBLESHOOTING
A. COMMON TROUBLES AND REMEDIES.
The following charts list the most common troubles
experienced with gasoline engines. Possible causes of
trouble are given along with probable remedy.
Remedy and Reference
Fill tank with clean, fresh fuel.
Open valve.
Clean fuel screen and line. If necessary, remove and clean
carburetor.
Flywheel key has sheared or partially sheared. Replace key.
Clean the vent or replace the cap.
Drain tank. Clean carburetor and fuel lines. Dry spark plug
points. Fill tank with clean, fresh fuel.
Close fuel shut-off, if so equipped, and pull starter until engine
starts. Reopen fuel shut-off for normal fuel flow.
Check ignition wiring for shorts or grounds; repair if
necessary.
Replace spark plug.
Replace spark plug.
Overhaul engine.
Check ignition air gap. If air gap is correct and there is no
spark at plug replace ignition.
See 12 volt starter troubleshooting chart.
Remove cylinder head and clean carbon from head and
piston.
Replace connecting rod.
Check flywheel key and keyway; replace parts if necessary.
Tighten flywheel nut to proper torque.
Replace cylinder.
Flywheel key has sheared or partially sheared. Replace key.
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