Instructions / Assembly

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9-7 HIGH FUEL CONSUMPTION
Phenomenon Possible causes Remedy
1. Fuel system
1) Over-size main jet Replace
2) Needle valve faulty and/or high fuel level in float
chamber
Adjust or replace
3) Chock valve does not open fully. Repair or replace
2. Engine core
components
1) Low compression Check or repair
2) Over cooling
Check and adjust load and/or engine
speed
9-8 DETONATION
Phenomenon Possible causes Remedy
1. Ignition
system
malfunction
1) Poor connection of ignition system wirings Check and connect properly
2) Improper or damaged spark plug Clean or replace
2. Fuel system
malfunction
1) Lean or rich air/fuel mixture Clean, adjust or replace
2) Carburetor damaged Disassembly and clean
3) Fuel lines clogged or damaged Clean or replace
4) Air mixing from connecting portion of air intake system Connect properly or replace gasket
3. Cylinder head
1) Carbon deposit in combustion chamber Remove and clean
2) Cylinder head gasket faulty (blow-by) Replace
4. Valve system
1) Improper valve clearance Adjust
2) Valve heat deterioration Replace
3) Valve spring deterioration Replace
4) Improper valve timing Adjust