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8. Troubleshooting
8-1 Engine does not start
Remove the spark plug from the cylinder. Put the spark plug on the outside of the cylinder.
Pull the recoil starter knob, and check whether sparks arise in the spark gap or not.
Trouble Probable
Cause
Countermeasure
No spark in the spark plug.
1. Wet spark plug electrodes
Make them dry.
2. Carbon deposited on the electrodes
Clean.
3. Insulation failure by insulator damage
Replace.
4. Improper spark gap
Adjust to
0.6
～
0.7 mm (0.023
～
0.028 in.).
Spark plug
5. Burn out of electrodes
Replace.
1. Ignition coil inside failure
Replace.
Magneto
2. Damaged cable sheath
Replace or repair.
1. Switch is OFF
ON the switch.
2. Switch is failure
Replace.
Switch
3. Primary wiring ground
Repair.
Sparks appear in the spark plug.
1. Over sucking of fuel
Drain excess fuel.
2. Too rich fuel
Adjust carburetor.
3. Overflow
Adjust or replace carburetor.
4. Clogging air cleaner
Wash with mixed gasoline.
Compression and
fueling is normal
5. Incorrect fuel
Change with proper fuel.
1. Worn out cylinder, piston, or piston ring
Replace.
Fueling normal but
poor compression 2. Gas leakage from cylinder and crank case gasket
Apply liquid gasket and reassemble.
1. Choked breather air hole
Clean.
2. Clogged carburetor
Clean.
No fuel supply
3. Clogged fuel filter
Replace fuel filter.
8-2 Engine stop during operation
Trouble Probable
Cause
Countermeasure
1. Switch is OFF
ON the switch.
2. Plug cap disconnect
Connect properly.
3. Short circuit by carbon deposited on the plug electrodes Clean.
4. Switch cord or high tension cord sheath worn out
Replace.
5. Ignition coil inside failure
Replace.
Suddenly stopped.
6. Engine seizure
Overhaul and replace damaged parts.
1. Lack of fuel
Refill.
2. Clogged carburetor
Clean.
Gradual speed
reduction and
stopped.
3. Water mixed to fuel
Drain and apply new fuel.
8-3 Engine cannot be stopped
Trouble Probable
Cause
Countermeasure
1. Lean fuel
Adjust carburetor.
2. Cylinder fin clogged with dusts
Clean.
3. Improper fuel
Change with proper fuel.
4. Carbon deposited inside of combustion chamber
Clean.
Overheating
5. Spark plug electrode red hot
Clean thoroughly and adjust spark gap
to 0.6
～
0.7mm (0.023
～
0.028in.).
1. Faulty switch
Replace.
Switch
2. Cord failure
Repair.
