3-4
Problem: Engine noisy (Noise seems to come from crankshaft)
Condition
Remedy
1.
Main bearing
worn - burned
2.
Lower rod-end bearing
worn - burned
3.
Connecting rod side clearance
too large
4.
Centrifugal clutch
loose
5.
Rotor/flywheel
loose
1. Replace bearing
2. Replace bearing
3. Replace crankshaft assembly
4. Tighten - replace clutch
5. Tighten - replace flywheel - crankshaft
Problem: Engine noisy (Noise seems to come from transmission)
Condition
Remedy
1.
Gears
worn - rubbing
2.
Splines
worn
3.
Primary gears
worn - rubbing
4.
Bearings
worn
5.
Bushing
worn
1. Replace gears
2. Replace shaft(s)
3. Replace gears
4. Replace bearings
5. Replace bushing
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.
ECU
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 magneto
6. Replace ECU
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 - service rings - cylinder
3. Replace guides
4. Replace cylinder
5. Replace valves
6. Replace seals
Manual
Table of Contents