Troubleshooting; Troubleshooting Of Engine (Fault Code Not Detected) - Yamaha YZ 2023 Series Owner's Service Manual

EAM20148

TROUBLESHOOTING

EAM30309
GENERAL INFORMATION
TIP
Troubleshooting information provided here does not cover all the trouble symptoms, possible causes,
and remedial actions. Some items may not apply depending on the model. Use this information as a
guide and quick reference matrix when performing basic troubleshooting. Refer to the each chapter for
detailed information on checking, adjustment, and replacement.
EAM30509

TROUBLESHOOTING OF ENGINE (fault code not detected)

TIP
If a fault code is detected, refer to the "FUEL INJECTION SYSTEM" on page 8-17.
Engine does not crank.
Symptom
Starter motor does not operate
Starter motor operates, but the
engine does not crank.
Engine will not start or is difficult to start, but it cranks.
Symptom
Spark plug does not produce a
spark
Fuel not supplied
Possible cause
Refer to "TROUBLESHOOTING" under "ELECTRIC STARTING
SYSTEM" on page 8-5.
Starter clutch malfunction
Improper oil grade (starter clutch
slipping)
Stuck piston or seized crankshaft
Possible cause
Refer to "TROUBLESHOOTING" under "IGNITION SYSTEM" on page
8-1.
—
Empty fuel tank
Clogged fuel tank cap breather
hole
Clogged or damaged fuel hose
Fuel leakage
Clogged fuel pump
Cracks or damage in fuel pump
Fuel pump malfunction
Failed or clogged fuel injector
ECU failure
9-1
TROUBLESHOOTING
Actions
Replace the starter clutch.
Change to recommended engine
oil.
Disassemble and check the
engine. Replace defective parts.
Actions
Measure the fuel pressure.
Fill the fuel tank with fuel.
Clean the fuel tank cap.
Clean, repair, or replace the fuel
hose.
Check the fuel passage. Repair or
replace as necessary.
Clean or replace the fuel pump.
Replace the fuel pump.
Refer to "TROUBLESHOOTING"
under "FUEL PUMP SYSTEM" on
page 8-43.
Replace the fuel injector.
Replace the ECU.