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Problem: Engine idles poorly
Condition
Remedy
1.
Gasoline
bad - contaminated
2.
Valve clearance
incorrect
3.
Valve seating
poor
4.
Valve guides
defective
5.
Magneto
defective
6.
ECM
defective
7.
Spark plug(s)
fouled -
gap
too wide
8.
Ignition coil
defective
9.
Fuel injector
obstructed
10.
Throttle body
dirty
1. Drain gas - replace with clean gas
2. Adjust clearance
3. Replace valves/cylinder head
4. Replace cylinder head
5. Replace stator coil
6. Replace ECM
7. Adjust gap - replace plug(s)
8. Replace ignition coil
9. Replace fuel injector
10. Clean bore and ISA passages
Problem: Engine runs poorly at high speed
Condition
Remedy
1.
Gasoline
bad - contaminated
2.
High RPM “cut out”
against RPM limiter
3.
Valve springs
weak
4.
Valve timing
incorrect
5.
Cams
worn
6.
Spark plug gap
too narrow
7.
Ignition coil
defective
8.
Air cleaner element
obstructed
9.
Fuel hose
obstructed
1. Drain gas - replace with clean gas
2. Shift into higher gear - decrease speed
3. Replace springs
4. Retime engine
5. Replace cams
6. Adjust gap
7. Replace ignition oil
8. Clean element
9. Clean - prime hose
Problem: Exhaust smoke dirty or heavy
Condition
Remedy
1.
Gasoline
bad - contaminated
2.
Engine oil
overfilled - contaminated
3.
Piston rings - cylinder
worn
4.
Valve guides
worn
5.
Cylinder wall
scored
6.
Valve stems
worn
7.
Stem seals
defective
1. Drain gas - replace with clean gas
2. Drain excess oil - change oil
3. Replace - service rings - cylinder
4. Replace cylinder head
5. Replace cylinder
6. Replace valves
7. Replace seals
Problem: Engine lacks power
Condition
Remedy
1.
Gasoline
bad - contaminated
2.
Valve clearance
incorrect
3.
Valve springs
weak
4.
Valve timing
incorrect
5.
Piston ring(s) - cylinder
worn
6.
Valve seating
poor
7.
Spark plug
fouled
8.
Spark plug gap
incorrect
9.
Fuel injector
obstructed
10.
Air cleaner element
obstructed
11.
Engine oil
overfilled - contaminated
12.
Intake manifold
leaking air
13.
Cam chain
worn
1. Drain gas - replace with clean gas
2. Adjust clearance
3. Replace springs
4. Time camshaft
5. Replace - service rings - cylinder
6. Repair seats
7. Clean - replace plug
8. Adjust gap - replace plug
9. Replace fuel injector
10. Clean element
11. Drain excess oil - change oil
12. Tighten - replace manifold
13. Replace cam chain - sprockets
Problem: Engine overheats
Condition
Remedy
1.
Carbon deposit (piston crown)
excessive
2.
Oil
low
3.
Octane
low -
gasoline
poor
4.
Oil pump
defective
5.
Oil filter
obstructed
6.
Intake manifold
leaking air
7.
Coolant level
low
8.
Fan
malfunctioning
9.
Fan relay
malfunctioning
10.
Thermostat
stuck - closed
11.
Radiator hoses - cap
damaged - obstructed
12.
Fan fuse(s)
blown
1. Clean piston
2. Add oil
3. Drain - replace gasoline
4. Replace pump
5. Replace filter
6. Tighten - replace manifold
7. Fill - examine system for leaks
8. Check fan fuse - replace fan
9. Replace fan relay
10. Replace thermostat
11. Clear obstruction - replace hoses - cap
12. Replace fuse(s)