Hitachi CS 51EA, Service Manual, Page: 2 / 35

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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
Disassembly and parts
replacement
Seized piston and cylinder
Faulty crank shaft bearings
Magneto rotor contact with
ignition coil
The recoil starter does
not rotate.
Broken recoil starter
Inspection and replacement
Faulty starter pawl
Startup is
impossible.
No compression
Faulty piston ring
Parts replacement
Worn piston
Expired oil seal service life
Worn cylinder
Defective sealing of the packing
Faulty decompression valve Cleaning or replacement
Short-circuited due to foreign matter between the spark plug
electrodes.
Removal of foreign matter: In
case of frequent occurrence,
disassemble and clean the
engine.
No spark
Stop switch not at startup position Adjust to startup position.
Dirty or faulty spark plug Cleaning or replacement
Improperly connected plug cap Inspection and replacement
Disconnected or improperly
connected high voltage cord
Repair or replacement
Ground connection of high
voltage cord
Repair
Disconnected or faulty ignition
coil ass’y
Replacement
Large gap between the magneto
rotor circumference and ignition
coil ass’y
Adjustment
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 Cleaning or replacement
Faulty fuel pipe
Adjustment, replacement or
connection
Faulty vent hole (inner cap) on
the fuel tank
Replacement
Faulty carburetor ass’y
Adjustment, cleaning or
replacement
The spark plug is wet
due to excessive fuel
supplied. Starter handle pulled repeatedly
with choke button pulled out (set
at “startup”)
Dry the spark plug.
Remove excessive fuel.
Idling stops
although
startup is
possible.
Weak spark
Dirty or faulty spark plug Cleaning or replacement
Improper air gap Adjustment
Low compression
Worn piston ring
Replacement
Expired oil seal service life
Faulty decompression valve Cleaning or replacement
Good spark and
compression
Revolutions too low for idling
Adjustment
Poorly adjusted carburetor ass’y
TROUBLESHOOTING GUIDE