23
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 - rubbing
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)
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.
CDI unit
defective
7.
Spark plug
fouled - gap too wide
8.
Ignition coil
defective
9.
Float
out of adjustment
10.
Jets
obstructed
11.
Pilot screw setting
improper
1. Adjust clearance
2. Replace - service seats - valves
3. Replace cylinder head
4. Replace arms - shafts
5. Replace magneto
6. Replace CDI unit
7. Adjust gap - replace plug
8. Replace ignition coil
9. Adjust float height
10. Clean jets
11. Adjust pilot screw
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 - tappets
worn
5.
Spark plug gap
too narrow
6.
Ignition coil
defective
7.
Float level
too low
8.
Air cleaner element
obstructed
9.
Fuel hose
obstructed
10.
Fuel pump
defective
1. Shift into higher gear - decrease speed
2. Replace springs
3. Adjust timing
4. Replace cams - arms - tappets
5. Adjust gap
6. Replace ignition oil
7. Adjust float height
8. Clean element
9. Clean or replace hose
10. Replace fuel pump
Problem: Exhaust smoke dirty or heavy
Condition
Remedy
1.
Oil (in the engine)
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 - replace oil
2. Replace - service rings - cylinder
3. Replace cylinder head
4. Replace - service cylinder
5. Replace valves
6. Replace seals
Problem: Engine lacks power
Condition
Remedy
1.
Valve clearance
incorrect
2.
Valve springs
weak
3.
Valve timing
incorrect
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.
Carburetor jets
obstructed
10.
Float level
out of adjustment
11.
Air cleaner element
obstructed
12.
Oil (in the engine)
overfilled - contaminated
13.
Intake manifold
leaking air
14.
Cam chain
worn
1. Adjust clearance
2. Replace springs
3. Re-time valve gear
4. Replace - service rings - cylinder
5. Repair seats
6. Clean - replace plug
7. Replace arms - shafts
8. Adjust gap - replace plug
9. Clean jets
10. Adjust float height
11. Clean element
12. Drain excess oil - change oil
13. Tighten - replace manifold
14. Replace cam chain
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.
Gasoline level (in float chamber)
too low
7.
Intake manifold
leaking air
8.
Fan
malfunctioning
9.
Fan switch
malfunctioning
1. Clean piston
2. Add oil
3. Drain - replace gasoline
4. Replace pump
5. Clean circuit
6. Adjust float height
7. Tighten - replace manifold
8. Check fan fuse - replace fan
9. Replace fan switch
Manual
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