Troubleshooting And Correction - Hitachi CM 75EAP Service Manual

1. Troubleshooting and correction

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