KEEWAY 500ATV, Service Manual

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14. Troubleshooting
14-3
Complaint Symptom and Possible Causes Remedy
Poor engine
running in
high-speed range.
1. Week valve spring
2. Worn camshaft
3. Fouled spark plug
4. Insufficient spark plug gap
5. Improper valve timing
6. Faulty ignition coil
7. Low fuel level in float chamber
8. Dirty air filter
9. Clogged fuel hose, resulting in poor fuel
supply
10. Clogged fuel valve
Replace
Replace
Clean or replace
Adjust or replace
Replace
Adjust float chamber fuel level
Clean or replace
Clean
Clean
Clean
Exhaust smoke is
dirty or thick
1. Excessive engine oil
2. Worn piston ring
3. Worn valve guide
4. Scored or scuffed cylinder wall
5. Worn valve stem
6. Worn valve stem oil seal Check oil level and drain
Replace
Replace
Replace
Replace
Replace
Engine lacks
power
1. Improper valve clearance
2. Weak valve spring
3. Improper valve timing
4. Worn cylinder
5. Worn piston ring
6. Improper valve seating
7. Fouled spark plug
8. Improper spark plug gap
9. Clogged carburetor jet
10. Improper fuel level in fuel chamber
11. Dirty air filter
12. Worn rocker arm or rocker arm shaft
13. Air leakage from air intake pipe
14. Excessive engine oil Adjust
Adjust
Adjust
Replace
Replace
Replace or Correct
Clean or replace
Clean or replace
Clean or replace
Adjust fuel level
Clean or replace
Replace
Tighten or replace
Check oil level and drain
Engine
overheats
1. Carbon deposit on piston top
2. Insufficient or excessive engine oil
3. Faulty oil pump
4. Clogged oil passage
5. Fuel level in float chamber is too low
6. Air leakage from air intake pipe
7. Incorrect engine oil
8. Faulty cooling system ( → 16-5)
Clean
Check level, add or drain
Replace
Clean
Adjust fuel level
Tighten or replace
Change engine oil
14