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1. Troubleshooting and correction
Trouble
Cause
Corrective action
Starter
handle
cannot be
pulled.
The crank shaft does
not rotate.
Faulty piston ring
Disassemble and
replace.
Seized piston and cylinder
Faulty crank shaft bearings
Magneto rotor contact with ignition coil
Clogging of dirt in starter pawl
Clean.
The recoil starter
does not rotate.
Broken recoil starter
Inspect and replace.
Startup is
impossible.
No compression
Faulty piston ring
Replace.
Worn piston
Expired oil seal service life
Worn cylinder
Defective sealing of the packing
Decompression valve trouble
Clean or replace.
Short-circuited due to foreign matter between the spark plug
electrodes.
Remove foreign matter:
In case of frequent
occurrence, replace the
spark plug and clean.
No spark
Stop switch not at startup position
Adjust to startup position.
Dirty or faulty spark plug
Clean or replace.
Improperly connected plug cap
Inspect and replace.
Disconnected or improperly connected
high voltage cord
Repair or replace.
Disconnected or faulty ignition coil
ass’y
Replace.
Large gap between the magneto rotor
circumference and ignition coil ass’y
Adjust.
The spark plug does
not become wet with
fuel after repeated
starting operation.
No fuel in the fuel tank
Add properly mixed fuel
(25:1 to 50:1).
Clogged fuel filter
Clean or replace.
Faulty fuel pipe
Adjust, replace or
connect.
Faulty vent hole (tank cap
inside plug)
on the fuel tank
Replace.
Faulty carburetor ass’y
Adjust, clean or replace.
The spark plug is wet
due to excessive fuel
supplied.
Pulling the starter handle several
times with the choke button at the
“startup” position
Dry the spark plug.
Remove residual fuel
from inside the cylinder
and crank case.
Idling stops
although
startup is
possible.
Weak spark
Dirty or faulty spark plug
Clean or replace.
Improper gap between the magneto
rotor circumference and ignition coil
ass’y
Adjust.
Low compression
Worn piston ring
Replace.
Expired oil seal service life
Decompression valve trouble
Clean or replace.
Good spark and
compression
Revolutions too low for idling
Adjust.
Poorly adjusted carburetor ass’y
TROUBLESHOOTING GUIDE