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Problem: Engine noisy (Noise seems to come from transmission)
Condition
Remedy
1.
Gears
worn - chipped
2.
Splines
worn
3.
Primary gears
worn - chipped
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 - chipped
6.
Splines
worn
1. Replace gears
2. Adjust backlash
3. Adjust contact
4. Replace bearing
5. Replace gears
6. Replace shaft(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.
Idle Step Control (ISC)
malfunction
1. Adjust clearance
2. Replace - service seats - valves
3. Replace cylinder head
4. Replace arms - shafts
5. Replace stator coil
6. Replace ECM
7. Adjust gap - replace plug
8. Replace ignition coil
9. Replace ISC
Problem: Engine runs poorly at high speed
Condition
Remedy
1.
High RPM “cut out”
against RPM limiter
2.
Valve springs
weak
3.
Valve timing
incorrect
4.
Cam - rocker arms - tappets
worn
5.
Spark plug gap
too narrow
6.
Ignition coil
defective
7.
Fuel pump
defective
8.
Air cleaner element
obstructed
9.
Fuel hose
obstructed
1. Shift into higher gear - decrease speed
2. Replace springs
3. Correct timing - check chain, sprockets, and cam chain ten-
sioner
4. Replace cam - arms - tappets
5. Adjust gap
6. Replace ignition coil
7. Replace fuel pump
8. Clean element
9. Clean or replace hose
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.
Air cleaner element
obstructed
10.
Oil (in the engine)
overfilled - contaminated
11.
Intake manifold
leaking air
12.
Cam chain
worn
1. Adjust clearance
2. Replace springs
3. Re-time valve gear
4. Replace - service rings - cylinder
5. Replace cylinder head/valves
6. Clean - replace plug
7. Replace arms - shafts
8. Adjust gap - replace plug
9. Clean element
10. Drain excess oil - change oil
11. Tighten - replace manifold
12. Replace cam chain