You can smell gas coming from your generator, but you’re not sure where it’s leaking. It can be difficult to find a leak especially if gas has already evaporated into the air leaving no wet spots indicating a leak.
A generator may begin leaking gas from the carburetor due to a worn carburetor bowl gasket or stuck float. It may also leak from the fuel filter, fuel lines, fuel tank, or fuel shut-off valve.
Always work in a well-ventilated area. Allow the generator to cool before troubleshooting and performing repairs.
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Follow all safety instructions provided in your equipment operator’s manual before diagnosing, repairing, or operating. Consult a professional if you don’t have the skills, or knowledge or are not in the condition to perform the repair safely.
This is Where a Generator May Begin Leaking Gas
A common place for a generator to begin leaking is from the carburetor. This is the place where a little fuel is stored after it leaves the fuel tank.
Gas sitting in the carburetor creates varnish that can cause its small parts to stick so it no longer regulates the amount of fuel allowed to enter the carburetor. This can cause it to overflow.
In addition to internal components no longer working right, the carburetor bowl gasket can fail and cause a leak.
Gasket failure in the carburetor bowl
Look to see if you find fuel leaking around the carburetor right above the bowl. There is a thin gasket that is used to seal the carburetor and bowl that can fail. When it no longer seals, gas will seep out of this area.
It is common for this gasket to become hard and brittle over time. Because it is located close to the engine, the gasket heats up when the engine is running and cools down when it is not.
This constant heating and cooling put a lot of stress on the gasket causing it to lose its sealing ability. When you find a leak in this area, it’s time to purchase a new carburetor bowl gasket and install it.
Steps to replace the carburetor bowl gasket:
- Shut off the fuel supply using the fuel shut-off valve. You can also use pinch pliers to crimp the fuel line to stop the flow if your generator doesn’t have a fuel valve.
- Wipe the outside of the carburetor so you don’t allow any dirt to enter the carburetor while removing the bowl.
- Have a rag or small container available to collect any fuel remaining in the bowl.
- The carburetor may have a screw located on the side of the bowl to empty the fuel bowl. If yours does, remove the screw, drain the fuel into a container, and replace the screw. If not, proceed with the next step.
- Remove the screw from the carburetor bowl and remove the bowl.
- Remove the old gasket and replace it with the new gasket.
- Reinstall the carburetor bowl.
- Reinstall the screw to hold the bowl and carburetor together.
- Wipe down the carburetor again to remove any spilled fuel
- Turn on the fuel supply and check for additional leaking from the carburetor.
Stuck float in the carburetor
Next, look for a fuel leak near the air intake port. When you find a leak in this area, you could have a stuck float that can no longer regulate fuel flow into the bowl.
Fuel keeps flowing into the carburetor bowl and then overflows out of the carburetor when you have a stuck float.
Take your carburetor apart when you find a stuck float to determine the actual cause of the failure. You may be able to clean the carburetor to keep the float from sticking.
You may also have to rebuild it to get the carburetor to work right or you may have to replace it with a new carburetor.
Stuck float needle in the carburetor
The last thing you should check on your carburetor is the float needle. The float needle works in conjunction with the float to keep gas flowing into the carburetor bowl. If the needle gets stuck, it will need to be repaired.
You will have to take your carburetor apart to fix the float or you can take it to your local small engine mechanic to have the carburetor rebuilt.
2. Cracked or Soft Fuel Filter
On most portable generators, you will find the fuel filter installed at the bottom of the fuel tank to keep dirt and other contaminants from entering the fuel system.
However, some generators may use a plastic inline filter placed in between the fuel lines. A plastic filter can begin leaking due to a crack or the plastic degrading. You must replace the fuel filter with a new one.
3. Fuel Tank Failure
Your generator may have a metal fuel tank or a high-density polyethylene tank. Whichever kind you have, they can both develop leaks as they age.
The seams can fail on the polyethylene tank resulting in a fuel leak. Fuel sitting in a metal tank can cause it to corrode and form rust spots that may eventually develop a hole.
The best thing to do when you find a leak in the fuel tank is to replace it with a new one.
However, if you have a metal tank on an older model that is no longer being manufactured, you may not have this option. You can attempt to repair the hole.
4. Faulty Shut-Off Valve
Check the fuel shut-off valve on your generator. It may be the spot your generator is leaking. Shut-off valves are prone to leaking and must be replaced when you find a leak.
The fuel shut-off valve may have a sediment bowl and seal. If it begins to leak around the bowl, remove the bowl and seal, clean the bowl, and install a new seal if available. Otherwise, replace the complete valve.
Replace a bad fuel shut-off valve.
5. Fuel Lines
Fuel lines can become dry and crack over time. If you find any cracks in the fuel lines, you must replace them with new lines. It’s best to replace lines that are dry and aged before they begin leaking.
In addition to looking at the age and condition of the lines, make sure the hose is securely connected to the fuel components and the fuel isn’t seeping. You may have to replace the clamps.