20
Problem: Engine noisy (Noise seems to come from secondary bevel gear and final driven shaft)
Condition
Remedy
1.
Drive - driven bevel gears
damaged - worn
2.
Backlash
excessive
3.
Tooth contact
improper
4.
Bearing
damaged
5.
Gears
worn - chipped
6.
Splines
worn
7.
Final driven shaft thrust clearance
too large
1. Replace gears
2. Adjust backlash
3. Adjust contact
4. Replace bearing
5. Replace gears
6. Replace shaft(s) - gears
7. Replace thrust washer(s)
Problem: Engine idles poorly
Condition
Remedy
1.
Valve clearance
out of adjustment
2.
Valve seating
poor
3.
Valve guides
defective
4.
Rocker arms - arm shaft
worn
5.
Magneto
defective
6.
ECM
defective
7.
Spark plug
fouled -
gap
too wide
8.
Ignition coil
defective
9.
Fuel injector
obstructed
1. Adjust clearance
2. Replace - service seats - valves
3. Replace guides
4. Replace arms - shafts
5. Replace stator coil
6. Replace ECM
7. Adjust gap - replace plug
8. Replace ignition coil
9. Replace fuel injector
Problem: Engine runs poorly at high speed
Condition
Remedy
1.
High RPM “cut out”
against RPM limiter
2.
Valve springs
weak
3.
Valve timing
out of adjustment
4.
Cams - rocker arms
worn
5.
Spark plug gap
too narrow
6.
Ignition coil
defective
7.
Air cleaner element
obstructed
8.
Fuel hose
obstructed
1. Shift into higher gear - decrease speed
2. Replace springs
3. Adjust timing
4. Replace cams - arms
5. Adjust gap
6. Replace ignition oil
7. Clean element
8. Clean - prime hose
Problem: Exhaust smoke dirty or heavy
Condition
Remedy
1.
Engine oil
overfilled - contaminated
2.
Piston rings - cylinder
worn
3.
Valve guides
worn
4.
Cylinder wall
scored - scuffed
5.
Valve stems
worn
6.
Stem seals
defective
1. Drain excess oil - change oil
2. Replace cylinder - service rings
3. Replace guides
4. Replace cylinder
5. Replace valves
6. Replace seals
Problem: Engine lacks power
Condition
Remedy
1.
Valve clearance
incorrect
2.
Valve springs
weak
3.
Valve timing
out of adjustment
4.
Piston ring(s) - cylinder
worn
5.
Valve seating
poor
6.
Spark plug
fouled
7.
Rocker arms - shafts
worn
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. Adjust clearance
2. Replace springs
3. Time camshaft
4. Replace cylinder - service rings
5. Repair seats
6. Clean - replace plug
7. Replace arms - shafts
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 circuit
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
1. Clean piston
2. Add oil
3. Drain - replace gasoline
4. Replace pump
5. Clean circuit
6. Tighten - replace manifold
7. Fill - examine system for leaks
8. Check fan fuse/fan relay - replace fan
9. Replace fan relay
10. Replace thermostat
11. Clear obstruction - replace hoses