Throttle opening fault Set in fully close or half close position
Carburetor faulty Adjust and/or disassemble and clean
Throttle control motor (stepping
motor) faulty
Inspect and replace
Inverter unit faulty Inspect and replace
Engine speed
does not
stabilize, too
high or too low
Valve clearance misadjusted Readjust
b. Hard starting
Remove the spark plug and
check for wet or fouled electrode.
Install a compression gauge in
the spark plug hole and check the
cylinder compression by pulling
the recoil starter rope several
times
Good spark
Install the spark plug securely.
Restart the engine according to
the starting procedure.
Normal
com
ression
Low
cylinder
compression
1. Check the valve clearance
2. Check for carbon deposits in the
combustion chamber.
3. Check for valve cone and base.
4. Check for worn piston, piston ring
or cylinder.
No spark or
weak spark
Perform the ignition system
troubleshooting
Clean the electrode and restart,
taking care that the choke is not
closed too much. If flooding is severe,
chec
the carburetor float valve.
Wet
Check the fuel level in the tank.
Loosen the drain screw and
check whether fuel reached the
carburetor.
Good spark
Remove the spark plug and
check for wet or fouled electrode.
Dry
Check for blockage in the carburetor
port and nozzle.
Fuel not reached
Add fuel and restart the engine.
Sufficient fuel
No fuel
Add fuel and restart the engine.
■ Cylinder compression check
1. Remove the spark plug cap and spark plug.
2. Install a compression gauge in the spark plug hole, pull the recoil starter rope several times with force
and measure the cylinder compression.
10