Trbl Shtg; Starting Failure/Hard Starting; Fuel System; Electrical System - Yamaha YFM50S Service Manual

STARTING FAILURE/HARD STARTING

EBS00537
NOTE:
_
The following troubleshooting does not cover all the possible causes of trouble. It should be helpful,
however, as a guide to troubleshooting. Refer to the relative procedure in this manual for check,
adjustment and replacement of parts.
STARTING FAILURE/HARD STARTING

FUEL SYSTEM

Fuel tank
• Empty
• Clogged fuel filter
• Clogged fuel strainer
• Clogged fuel breather hose
• Deteriorated or contaminated fuel
Fuel cock
• Clogged fuel hose
Carburetor
• Deteriorated or contaminated fuel
• Clogged pilot jet
• Clogged pilot air passage
• Sucked-in air
• Deformed float
• Worn needle valve
• Improperly sealed valve seat
• Improperly adjusted fuel level
• Improperly set pilot jet
Air filter
• Clogged air filter element
TROUBLESHOOTING

ELECTRICAL SYSTEM

Spark plug
• Improper plug gap
• Worn electrodes
• Wire between terminals broken
• Improper heat range
• Faulty spark plug cap
Ignition coil
• Broken or shorted primary/secondary
• Faulty spark plug lead
• Broken body
C.D.I. system
• Faulty C.D.I. unit
• Faulty pickup coil
• Faulty source coil
• Broken woodruff key
Switches and wiring
• Faulty main switch
• Faulty engine stop switch
• Broken or shorted wiring
• Faulty neutral switch
• Faulty start switch
Starter motor
• Faulty starter motor
• Faulty starter relay
• Faulty starter circuit cut-off relay
Battery
• Faulty battery
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TRBL
SHTG
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