Rough Idling - Yamaha 20C Service Manual

TRBL
SHTG
O50000-0*
Is the fuel fresh?
Are all wiring connections tight?
Are the spark-plugs tightly screwed in?
Does sparking take place in all cylinders?
Is the lighting coil used to supply a heavy load?
Are the ignition sequence and timing correct?
Are the settings of the carburettor correct?
Is the magneto base loose?
Does the reed-valve seal effectively?
Does the flywheel have excessive run-out?
Does the fuel-pump operate normally?
Does the compression meet the specified pres-
sure?
RE-CHECK

ROUGH IDLING

ROUGH IDLING
YES
YES
YES
YES
NO
YES
YES
NO
YES
NO
YES
YES
NO
Replace the fuel.
NO
Tighten.
NO
Tighten. (P.3-14)
NO
3
GO TO
YES
Disconnect the load.
NO
Correct this. (P.3-9 – 3-12)
NO
Correct the setting. (P.3-8)
YES
Tighten.
NO
Replace the reed-valve.
YES
Check the crankshaft (P.5-20)
NO
Replace.
NO
Inspect the cylinder piston head gasket
and piston rings for wear and damage.
(P.5-15, 5-19)
9-6
(P.9-4)
E