This chapter covers information and servicing procedures for the fuel system components of motorcycles scooters, UTV’s and ATVs.
TROUBLESHOOTING
Engine cranks but won’t start
- No fuel in tank
- No fuel to carburetor
- Cylinder flooded with fuel
- No spark at plug
- Clogged air cleaner
- Intake air leak
- Improper throttle operation
- Compression too low
- Contaminated fuel
- Faulty auto bystarter
- Clogged idle system or auto bystarter passages
Engine lacks power
- Clogged air cleaner
- Faulty carburetor
- Faulty ignition system
Lean mixture
- Clogged carburetor fuel jets
- Float level too low
- Faulty float valve
- Intake air leak
- Clogged fuel tank cap breather hole
- Bent, kinked or restricted fuel line
Rich mixture
- Float level too high
- Clogged air jets
- Clogged air cleaner
- Faulty auto bystarter
- Faulty float valve
Engine idles roughly, stalls or runs poorly
- Clogged fuel system
- Faulty auto bystarter (electric choke)
- Ignition malfunction
- Faulty carburetor
- Poor quality fuel
- Lean or rich mixture
- Incorrect idle speed
- Contaminated fuel
- Intake air leak
- Incorrect pilot screw adjustment
- Float level incorrect
Misfiring during acceleration
- Faulty ignition system
- Faulty carburetor
- Faulty accelerator pump
Backfiring at deceleration
- Float level too low
- Incorrectly adjusted carburetor
- Lean mixture in idle system