Yamaha F40BED, Service Manual

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TRBL
ANLS
9-4
TROUBLE SHOOTING FOR PEAK VOLTAGE
E
TROUBLE SHOOTING FOR PEAK VOLTAGE
Items Symptoms
1. Poor starting • No firing. The starter motor cranks the engine, but no firing takes
place in the cylinder.
• Firing takes place in the cylinder, but the engine stops soon.
• Start-up time is too long. The engine will not start-up easily.
2. Unstable idling
speed • The engine speed is not stable at idle.
• The engine stalls when the throttle lever is opened.
• The engine stalls after it is warmed-up.
3. Unstable engine
speed • The engine does not run smoothly.
• The engine speed drops during acceleration.
Check the ignition system.
1) Check the wire harness couplers to ignition coil, CDI unit, pulser coil, and charge coil.
NG
Contamination, Loose connection Clean
Corrosion Correct
OK
2) Check the spark gap.
OK
Above specification Replace the spark plug.
NG
3) Check the plug cap.
NG
Out of specification Replace.
OK
4) Check the ignition coils.
NG
Out of specification Replace.
OK
5) Check the CDI unit output peak voltage.
OK
Above specification Replace the ignition coil.
NG
6) Check the charge coil output peak voltage.
NG
Below specification Replace the charge coil.
OK
7) Check the pulser coil output peak voltage.
NG
Below specification Replace the pulser coil.
OK
Replace the CDI Unit.