Symptoms
- Strong gasoline smell near the carburetor
- Fuel dripping from the carburetor overflow tube
- Bike is hard to start and smells heavily of gas, suggesting it's over-fueled
Likely causes
- CommonStuck float needle valveDebris or varnish from old fuel can prevent the needle valve from sealing, letting fuel overflow continuously.
- PossibleWorn or punctured floatA float that doesn't rise properly (due to wear or a fuel-saturated foam float) won't shut off the fuel inlet at the right level.
- CommonDirty or stale fuel leaving deposits on the needle seatOld fuel varnish is a very common cause after a bike sits for weeks or months.
What to do
- Turn off the fuel petcock immediately if you smell strong gas or see fuel dripping, to stop feeding the flood.
- Tap the carburetor body gently near the float bowl with a wrench handle; this sometimes dislodges debris stuck in the needle valve enough to reseat it.
- If tapping doesn't help, the float bowl will need to be removed to inspect and clean the float, needle valve, and seat.
- Clean out any varnish or debris from the fuel bowl and passages, and check the float for proper movement and no fuel absorption (in older foam floats).
- Reassemble and test with the petcock on, watching closely for any continued dripping from the overflow.
- If the bike sat for a long period with old fuel, consider draining the tank and using fresh fuel with a stabilizer going forward.
Tools and parts
- Basic hand tools
- Carburetor cleaner
- Fuel-safe drain pan
Carburetor rebuild kit for your bike, if neededSearch: “carburetor rebuild kit for [your bike year make model]”
When to call a pro
If flooding continues after cleaning, or you're not comfortable disassembling the carburetor, a motorcycle mechanic can rebuild or replace it.
Safety
Use caution
Fuel flooding creates a fire hazard; keep sparks and flames away and clean up any spilled fuel immediately.