Fuel System Troubleshooting - Honda TRX450R Service Manual

FUEL SYSTEM ('04-'05)
TROUBLESHOOTING
Engine cranks but won't start
• No fuel in tank
• No fuel to carburetor
- Clogged fuel strainer
- Clogged fuel line
- Clogged fuel tank breather hose
• Too much fuel getting to the engine
- Clogged air cleaner
- Flooded carburetor
• Intake air leak
• Contaminated/deteriorated fuel
- Clogged jets
• Clogged starting enrichment (SE) valve circuit
• Improper choke operation
• Improper throttle operation
• No spark at plug (faulty ignition system - page 20-5)
Lean mixture
• Clogged fuel jets
• Faulty float valve
• Float level too low
• Restricted fuel line
• Clogged carburetor air vent hose
• Restricted fuel tank breather hose
• Intake air leak
• Faulty throttle valve
Rich mixture
• SE valve open
• Clogged air jets
• Faulty float valve
• Float level too high
• Dirty air cleaner
• Worn jet needle or needle jet
Engine stalls, hard to start, rough idling
• Restricted fuel line
• Fuel mixture too lean/rich
• Contaminated/deteriorated fuel
- Clogged jets
• Intake air leak
• Misadjusted idle speed
• Restricted fuel tank breather hose
• Dirty air cleaner
• Misadjusted pilot screw
• Clogged slow circuit or SE valve circuit
• Faulty ignition system (page 20-5)
Afterburn when engine braking is used
• Lean mixture in slow circuit
• Faulty ignition system (page 20-5)
Backfiring or misfiring during acceleration
• Lean mixture
• Faulty ignition system (page 20-5)
Poor performance (driveability) and poor fuel economy
• Clogged fuel system
• Faulty ignition system (page 20-5)
7-4