-9-
Piston ring is damaged
Replacement
Piston or cylinder is stuck
Replacement
Needle bearing on connecting rod is damaged
Replacement
Ball bearing is stuck
Replacement
Magneto rotor touches the ignition coil
Inspection and
adjustment
Recoil starter is damaged
Inspection and
replacement
Valve is damaged
Replacement
Oil pump (inner or outer rotor) is
damaged
Replacement
Crank gear or cam gear is damaged
Replacement
Stop switch is not set to starting position
Setting the switch to
starting position
Spark plug is stained or faulty
Cleaning and
inspection
High-voltage cord or other cable broke,
or its connection is faulty
Inspection
High-voltage cord or other cable is
grounded
Inspection
Ignition coil broke or is faulty
Replacement
Clearance between magneto rotor and
ignition coil is too large
Adjustment
Fuel filter (pump filter body assembly)
was clogged
Cleaning or
replacement
Fuel pipe is cracked or creased
Replacement
Air hole on tank cap is faulty
Replacement
Pump diaphragm of carburetor is faulty
Replacement
Carburetor is clogged with foreign matter
Cleaning
Piston ring is faulty
Replacement
Piston ring is worn
Replacement
Piston is worn
Replacement
Cylinder is worn
Replacement
Cam is damaged
Replacement
Crank gear or cam gear is damaged
Replacement
Valve is damaged
Replacement
Carbon accumulated on a sealed valve
surface
Cleaning
Fuel filter (pump filter body assembly) is
clogged
Cleaning or
replacement
Warm-up is insufficient especially in a
cold environment
Warm-up operation
Valve clearance is extended
Inspection and
adjustment
Repair Flowchart
OK
NG
OK
NG
The engine stalls
Pull the starter handle.
Check whether there is
compression and the handle ca
be pulled
The engine starts.
Pull the throttle lever, and
check what happens
NG
OK
Check whether there is
compression
OK
OK
NG
Remove the spark plug.
Check whether the plug sparks
Mount the sparek plug and spark
plug cap, and perform correct
startup operation.
Check whether the spark plug
head is wet with fuel