Fuel System Troubleshooting; Engine Won't Start; Engine Stall, Hard To Start, Rough Idling; Lean Mixture - Honda 2003 NPS50 Ruckus Service Manual

FUEL SYSTEM
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TROUBLESHOOTING

Engine won't start

No fuel in tank
No fuel to carburetor
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- Clogged fuel filter
- Clogged fuel hose
- Clogged fuel cap breather hole
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- Faulty fuel pump (page 1 9-18)
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Too much fuel getting to the engine
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- Clogged air cleaner
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- Flooded carburetor
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Intake air leak
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Contaminated/deteriorated fuel
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Faulty starting enrichment (SE) valve
Clogged starting enrichment (SE) circuit
Clogged carburetor slow circuit
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Improper throttle operation
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No spark at plug (faulty ignition system - page 17-5)
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Engine stall, hard to start, rough idling

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Restricted fuel line
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Fuel mixture too lean/rich
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Contaminated/deteriorated fuel
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Intake air leak
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Misadjusted idle speed
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Misadjusted pilot screw
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Clogged fuel filler cap breather hole
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Clogged air cleaner
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Clogged slow circuit
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Faulty starting enrichment (SE) valve
Faulty foot level
Faulty fuel pump (page 19-18)
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Faulty ECT sensor (page 1 9-1 5)
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Faulty ignition system (page 17-5)
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Lean mixture

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Clogged fuel jets
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Faulty float valve
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Float level too low
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Restricted fuel line
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Clogged carburetor vacuum hose
Clogged fuel filler cap breather hole
Intake air leak
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Faulty diaphragm/vacuum piston
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Faulty fuel pump (page 1 9-18)
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Rich mixture
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Clogged air jet
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Faulty float valve
Float level too high
Starting enrichment {SE) valve stucl< open
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Clogged air cleaner
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Flooded carburetor
Backfiring or misfiring during acceleration
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Fuel mixture too lean
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Faulty ignition system (page 17-5)
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Afterburn when engine braldng is used
Lean mixture in slow circuit
Faulty ignition system (page 17-5)
Faulty pulse secondary air injection (PAIR) system
- Faulty PAIR control valve
- Faulty PAIR check valve
- Clogged hose of the PAIR system
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