TROUBLESHOOTING
ENGINE
Complaint Symptom and possible causes Remedy
Engine does not start,
or is hard to start.
Compression too low
1. Excessively worn cylinder or piston rings.
2. Stiff piston ring in place.
3. Gas leaks from the joint in crankcase, cylinder or cylinder
head.
4. Damaged reed valve.
5. Spark plug too loose.
6. Broken, cracked or otherwise failed piston.
Plug not sparking
1. Damaged spark plug or spark plug cap.
2. Dirty or wet spark plug.
3. Defective CDI & ignition coil unit or stator coil.
4. Open or short n high-tension cord.
5. Defective ignition switch.
No fuel reaching the carburetor
1. Clogged hole in the fuel tank cap.
2. Clogged or defective fuel cock.
3. Defective carburetor float valve.
4. Clogged fuel hose or defective vacuum hose.
Replace.
Repair or replace.
Repair or replace.
Replace.
Tighten
Replace.
Replace.
Clean and dry.
Replace.
Replace.
Replace.
Clean.
Clean or replace.
Replace.
Clean or replace.
Engine stalls easily. 1. Carbon deposited on the spark plug.
2. Defective CDI & ignition coil unit.
3. Clogged fuel hose.
4. Clogged jets in carburetor.
5. Clogged exhaust pipe.
Clean.
Replace.
Clean.
Clean.
Clean.
Noisy engine. Noise appears to come from piston
1. Piston or cylinder worn down.
2. Combustion chamber fouled with carbon.
3. Piston pin, bearing or piston pin bore worn.
4. Piston rings or ring grooves worn.
Noise seems to come from crankshaft
1. Worn or burnt crankshaft bearings.
2. Worn or burnt conrod big-end bearings.
Noise seems to come from final gear box
1. Gears worn or rubbing.
2. Badly worn splines.
3. Worn or damaged bearing of drive shaft or rear axle shaft.
Replace.
Clean.
Replace.
Replace.
Replace.
Replace.
Replace.
Replace.
Replace.
Slipping clutch 1. Worn or damaged clutch shoes.
2. Worn clutch drum.
Replace.
Replace.
Engine idles poorly. 1. Excessively worn cylinder or piston rings.
2. Stiff piston ring in place.
3. Gas leaks from crankshaft oil seal.
4. Spark plug gaps too wide.
5. Defective CDI & ignition coil unit.
6. Defective magneto stator coil.
7. Float-chamber fuel level out of adjustment in carburetor.
8. Clogged jets in carburetor.
9. Broken or damaged reed valve.
Replace.
Replace.
Replace.
Adjust or replace.
Replace.
Replace.
Replace.
Clean or adjust.
Replace.
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