A Honda Lawn Mower With a Gas Leak in the Front

Fuel Tank Cap

• Gas leaks often occur at the fuel tank cap. The engine constantly vibrates during operation and this vibration can jar loose the rubber seal on the inner ring of the fuel cap. Also, this rubber seal may get lost during a refueling stop, which may have gone unnoticed until the gas leak. Unscrew the fuel tank cap and make sure a rubber ring fits around the inside of the cap, near the end of the threads. If no rubber ring is present on the cap, replace the fuel tank cap.

Fuel Tank

• Fuel can also start leaking from the tank itself. Rocks, glass and other sharp objects may accidentally puncture a tiny hole in the plastic tank. This hole, through continuous vibration, may enlarge enough to leak a small amount of gas. Puncture marks are difficult to detect. Wipe off the outside of the fuel tank cap with a rag. Run a finger slowly along the plastic, checking for any minor perforations. If a leak in the tank is suspected, replace the entire fuel tank.

Fuel Hoses

• Fuel runs from the tank into the carburetor and back to the tank via two plastic hoses. These hoses will degrade over time. If these hoses take an additional hit from a rock or heavy bump, a small rip or perforation may start a gas leak on the hoses. Check the fuel hoses to see if they are starting to turn brown and brittle to the touch. Replace the fuel hoses at least every other season or more frequently if you consistently run the mower in dusty, dirty conditions.

Carburetor Seals

• The carburetor needs to maintain an airtight seal with the entire fuel system. If any of these sealing points get broken, gas may slowly start to leak out any part of the engine. Make sure the fuel hoses are tightly fastened to the carburetor elbows an use a press fluid to keep the airtight seal when replacing them. Replace the gaskets every time you remove the carburetor. If leaking continues, take the lawn mower to a mechanic to look at internal parts of the engine.