– 32 –
Problem and possible cause
Remedy
Exessive engine oil consumption
High fuel consumption
Abnormal engine noise
1. Oil leakage
1) Loose oil drain plug
Tighten
2. Oil up
1) Faulty piston oil ring
Replace
1. Fuel system
1) Clogged air cleaner
Clean or replace
2. Engine core components 1) Low compression
Check and repair
1. Ignition system problems 1) Loose ignition system wiring
Inspect and tighten
2. Fuel system problems
1) Lean or rich fuel/air mixture
Clean, adjust or replace
carburetor
3. Cylinder head
1) Carbon deposit in combustion chamber
Clean
4. Valve system problems
1) Improper valve clearance
Adjust
Adjust
Replace
2) Faulty oil drain gasket
Replace
3) Loose main bearing cover bolts
Tighten
4) Faulty main bearing cover gasket
Replace
5) Crankshaft oil seal (front, rear) defect
Repair or replace
2) Piston ring seizure, wear or poor contact
Replace
3) Excessive wear of piston and/or cylinder
Replace
4) Faulty stem seal
Replace
5) Excessive oil level
Adjust oil level
6) Breather defect
Repair or replace
2) Faulty needle valve and/or high fuel level in
float chamber
Repair or replace
3) Choke does not open fully
Check and adjust load
and/or engine speed
2) Overcooling
Clean or replace
2) Improper or faulty spark plug
Tighten; replace gasket
2) Carburetor contamination
Overhaul or clean
3) Dirty or clogged fuel lines
Clean or replace
4) Air mixing from air intake system joints
Replace
2) Leakage from cylinder head gasket
2) Valve heat deterioration
Replace
3) Worn or broken valve spring
Replace
4) Improper valve timing
