4
Repair Manual PS-6400/PS-7300/PS-7900
TROUBLESHOOTING
Malfunction
System
Observation
Cause
Chain does not run
Chain brake
Engine runs
Chain brake actuated.
Engine does not start or
Ignition system
Ignition spark
Malfunction in fuel supply system, com-
only with difficulty
pression system, mechanical malfunction.
No ignition spark
Switch on STOP, fault or short-circuit in the
wiring, plug cap or spark plug defective.
Fuel supply
Fuel tank is filled
Choke in wrong position, carburetor defective,
fuel filter dirty, fuel line bent or interrupted, torn,
perforated
Compression
Inside
Cylinder base packing ring defective, radial
system
shaft packings defective, cylinder or piston rings
defective
Outside
Spark plug does not seal.
Mechanical
Starter does not engage
Spring in starter broken, broken parts
malfunction
inside the engine.
Warm engine doesn‘t
Carburetor
Fuel tank is filled
Wrong carburetor adjustment,
start
Ignition spark
flooded by usage of the ckoke
Engine starts, but
Fuel supply
Fuel tank is filled
Wrong idling adjustment, fuel filter or
dies immediately
carburetor dirty. Tank venting defective, fuel
line interrupted, cable defective, STOP switch
defective. Decompression valve dirty
Insufficient power
Several systems
Engine is idling
Air filter dirty, wrong carburetor adjustment,
may be involved
muffler clogged, exhaust channel in cylinder
simultaneously
clogged, spark arrester screen clogged, worn piston
No chain lubrication
Oil tank/pump
No oil on the chain
Oil tank empty, oil guide groove dirty,
oil-pump adjusting screw incorrectly adjusted,
oil pump drive defective