Symptoms
- Won't start despite good spark and fresh fuel added recently
- Runs rough, surges, or stalls even after some fresh fuel is added
- Fuel smells stale when the tank is opened
- Has been sitting unused for months or longer
Likely causes
- CommonOld fuel left in the carburetor bowl evaporated and left varnishThis is extremely common after off-season storage without draining fuel or using stabilizer.
- PossibleDebris or rust particles clogging small jetsCan accompany varnish buildup, especially if the fuel tank has any rust or the fuel was contaminated.
- PossibleFloat or float needle stuck from gum depositsA stuck float can cause flooding or fuel starvation depending on how it's stuck.
What to do
- Drain any old fuel from the tank and carburetor bowl into an approved container.
- Locate the carburetor drain screw (if equipped) to fully empty the bowl, or remove the bowl per your model's manual.
- Spray carburetor cleaner into all accessible passages, jets, and the bowl, letting it soak per the product's instructions.
- Use fine wire (never a drill bit, which enlarges the jet) to clear stubborn blockages in small jets.
- Check the float moves freely and isn't sticking, cleaning around its pivot if needed.
- Reassemble with a new bowl gasket if the old one is damaged, refill with fresh fuel, and attempt to start.
- If cleaning doesn't fully restore normal running, a full carburetor rebuild kit (with new gaskets, needle, and seats) or professional service is the next step.
Tools and parts
- Carburetor cleaner spray
- Small wrench set
- Fine wire (not a drill bit)
Carburetor rebuild kitSearch: “small engine generator carburetor rebuild kit”
Carburetor bowl gasketSearch: “generator carburetor bowl gasket”
When to call a pro
If you're not comfortable removing and cleaning the carburetor, a small-engine shop can do a full cleaning or rebuild, usually within a day or two.
Safety
Use caution
Work outdoors or in a well-ventilated area away from ignition sources when handling fuel and carburetor cleaner.