Yamaha PW50W 2007 Service Manual page 162

ELECTRICAL SYSTEM
Spark plug(s)
9 Incorrect spark plug gap
9 Incorrect spark plug heat range
9 Fouled spark plug
9 Worn or damaged electrode
9 Worn or damaged insulator
9 Faulty spark plug cap
Ignition coil(s)
9 Cracked or broken ignition coil body
9 Broken or shorted primary or secondary
coils
9 Faulty spark plug lead
EAS28490
INCORRECT ENGINE IDLING SPEED
ENGINE
Air filter
9 Clogged air filter element
FUEL SYSTEM
Carburetor(s)
9 Faulty starter plunger
9 Loose or clogged pilot jet
9 Loose or clogged pilot air jet
9 Damaged or loose carburetor joint
9 Improperly adjusted engine idling speed
9 Improper throttle cable free play
9 Flooded carburetor
STARTING FAILURES/
INCORRECT ENGINE IDLING SPEED
8-2
Ignition system
9 Faulty CDI unit
9 Faulty pickup coil
9 Faulty charge coil
9 Faulty lighting coil
9 Faulty control unit
9 Faulty diode
9 Broken generator rotor woodruff key
Switches and wiring
9 Faulty ignition control switch
9 Broken or shorted wiring
9 Improperly grounded circuit
9 Loose connections
ELECTRICAL SYSTEM
Spark plug(s)
9 Incorrect spark plug gap
9 Incorrect spark plug heat range
9 Fouled spark plug
9 Worn or damaged electrode
9 Worn or damaged insulator
9 Faulty spark plug cap
Ignition coil(s)
9 Broken or shorted primary or secondary
coils
9 Faulty spark plug lead
9 Cracked or broken ignition coil
Ignition system
9 Faulty CDI unit
9 Faulty pickup coil
9 Faulty charge coil
9 Faulty lighting coil
9 Faulty control unit
9 Faulty diode
9 Broken generator rotor woodruff key
TRBL
SHTG