1.
Engine difficult to start
Check fuel level in tank.
Adequate fuel in
tank
Operate manual fuel pump
and check that fuel is flowing to
carburetor.
Fuel flows to
carburetor
Remove spark plug and
check for damp or oily
electrodes.
Damp
Check spark plug
for spark.
Powerful spark
Check compression.
Adequate compression
Install spark plug and start
engine according to
instructions.
No fuel
Fuel does not flow
to carburetor
Dry
No spark or only a
weak spark
Compression in order
Compression too low
Fill up with fuel and try starting
again.
– Check fuel line and fuel
filter for blockages.
– Faulty carburetor diaphragm
or float needle valve,
replace carburetor
Replace carburetor
– Change spark plug and
repeat the spark test.
– Check ignition lead for
damaged insulation and
leakage current.
– Check ignition coil.
Check combustion chamber
for excessive build-up of
combustion deposits.
– Check, adjust valve
clearance.
– Valves must be in good
condition.
– Check piston, rings and
cylinder for wear.
FS 25-4, 65-4
7
