3-4
Troubleshooting
Problem: Engine will not start or is hard to start (Compression too low)
Condition
Remedy
1.
Valve clearance
out of adjustment
2.
Valve guides
worn
3.
Valves
mistimed
4.
Piston rings
worn excessively
5.
Cylinder bore
worn
6.
Starter motor
cranks too slowly - does not turn
1. Adjust clearance
2. Repair - replace guides
3. Retime engine
4. Replace rings
5. Replace - rebore cylinder
6. See Section 5 - Troubleshooting
Problem: Engine will not start or is hard to start (No spark)
Condition
Remedy
1.
Spark plug
fouled
2.
Spark plug
wet
3.
Magneto
defective
4.
CDI unit/ECU
defective
5.
Ignition coil
defective
6.
High-tension lead
open - shorted
1. Clean - replace plug
2. Clean - dry plug
3. Replace magneto
4. Replace CDI unit/ECU
5. Replace ignition coil
6. Replace high tension lead
Problem: Engine will not start or is hard to start (No fuel reaching the carburetor/fuel injector)
Condition
Remedy
1.
Gas tank vent hose
obstructed
2.
Carburetor float valve
defective
3.
Fuel hose
obstructed
4.
Fuel screens
obstructed
5.
Fuel pump
defective
1. Clean vent hose
2. Replace valve
3. Clean - replace hose
4. Clean - replace inlet screen - valve screen
5. Replace fuel pump
Problem: Engine stalls easily
Condition
Remedy
1.
Spark plug
fouled
2.
Magneto
defective
3.
CDI unit/ECU
defective
4.
Carburetor jets/fuel injector
obstructed
5.
Valve clearance
out of adjustment
1. Clean plug
2. Replace magneto
3. Replace CDI unit/ECU
4. Clean jets/replace fuel injector
5. Adjust clearance
Problem: Engine noisy (Excessive valve chatter)
Condition
Remedy
1.
Valve clearance
too large
2.
Valve spring(s)
weak - broken
3.
Rocker arm - rocker arm shaft
worn
4.
Camshaft
worn
5.
Valve tappets
worn
1. Adjust clearance
2. Replace spring(s)
3. Replace arm - shaft
4. Replace camshaft
5. Replace tappets
Problem: Engine noisy (Noise seems to come from piston)
Condition
Remedy
1.
Piston
- cylinder
worn
2.
Combustion chamber
carbon buildup
3.
Piston pin - piston pin bore
worn
4.
Piston rings - ring groove(s)
worn
1. Replace - service piston - cylinder
2. Clean cylinder head and piston
3. Replace - service pin - bore
4. Replace rings - piston
Problem: Engine noisy (Noise seems to come from timing chain)
Condition
Remedy
1.
Chain
stretched
2.
Sprockets
worn
3.
Tension adjuster
malfunctioning
1. Replace chain
2. Replace sprockets
3. Repair - replace adjuster
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