Service Manual

TROUBLESHOOTING 8-5
[Fuel consumption is excessive]
Is compression sufficient?
@High fuel level in carb. float -Adjust
chamber (including overflow).
0 Faulty igniter. - Replace
l High idling R.P.M.
-Adjust
l Choke partially closed. - Open choke
0 Excessively backed off carbu- - Adjust
retor pilot screw.
[Oil consumption is excessive]
I Is compression sufficient?
l Worn piston/piston rings. - Replace
@Stuck piston.
- Clean or replace
l Worn cylinder bore. - Bore or replace
l Insufficient cyl. head tightness. - Retighten
l Faulty valve seat contact. - Lap
l Plunge-up of valve. - Adjust valve clearance
l Wrong valve timing. - Adjust
0 Broken valve spring. - Replace
l Stuck valve.
- Clean or grind
h-YES-
I
’ L
NO-
0 Plugged oil ring groove.
Clean
0 High oil level. Adjust
@Worn valve stems and valve Lap
guide.
Replace
OOil leakage along governor
shaft.
*Oil leakage from oil seal.
@Oil leakage from mounting
surface.
l Oil leakage from drain plug.
@Clogged breather valve.
@Drain-back hole in breather
chamber plugged.
0 Incorrect oil viscosity.
-
Replace
Replace
Replace gasket
Retighten or replace gasket
Clean
Clean
Correct
[Engine runs erratically]
I
[Engine backfires]
.
@Dirt or water in fuel line.
- Clean
l Carb. not properly adjusted.
- Adjust
@Spark plug fouled, pitted, or - Replace or adjust
gapped incorrectly.
l Carb. flange leaking at gasket. - Tighten or replace
l Carb. body and throttle shaft - Replace
warn.
0 Restricted gas tank vent.
l Governor malfunctioning.
- Clean
- Adjust
0 Loose carb. or intake manifold.
0 Loose cyl. head or leaking head
[Engine knocks]
-
l Excessive carbon deposit in
0 Excessive engine load.