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How to Repair a Lawn Mower With the Wrong Fuel Added

By Michael Rippetoe ; Updated September 21, 2017

No mower will run without gasoline in the tank, so always check the fuel level before using the mower. If the wrong fuel was added to the tank, this will cause the mower to stop running, or in some cases, not run at all. But the process to remove the wrong fuel is quick.

Locate the fuel tank on the mower. Many mowers locate the fuel tank under the hood of the mower, although some will place the tank under the seat.

Locate the fuel line connection on the tank. This connection will be on the bottom of the tank.

Place the bucket under the tank's fuel line connection. On some mowers this cannot be done because of the location of the connection. For these mowers the fuel line connection on the engine will have to be used.

Remove the fuel line from the tank or engine by squeezing the clamp on the fuel line with the pliers and sliding it away from the tank or engine. Then wiggle the line off of the fuel barb on the tank or engine.

Allow the fuel system to completely drain. Remove the fuel cap to speed this process.

Remove the bowl from the bottom of the carburetor. The carburetor is located where the fuel line connects to the engine. Most fuel bowls have a center nut that hold them to the carburetor. Use the adjustable wrench to remove the bowl.

Wipe the bowl clean with paper towels. This will remove the majority of the wrong fuel from the fuel bowl.

Reinstall the fuel bowl to the carburetor. Do not cross-thread the bolt when reinstalling. (Cross-threading is when the threads of the bolt cut new threads across the threads of the hole where the bolt is installed.) Cross-threading the bolt will not allow the fuel bowl to seal properly and require the carburetor to be replaced.

Reinstall the fuel line to the tank or engine connection by pressing the fuel line back on the barb and then sliding the clamp back over the barb.

Fill the tank with the proper fuel.


Things You Will Need

  • 5-gallon bucket
  • Pliers
  • Adjustable wrench
  • Paper towels


  • Fuel line cleaner can be added to the correct fuel to help further clean the fuel system.


  • Make sure to properly dispose of the fuel that came out of the fuel system.
  • If the mower ran with the wrong fuel, have it checked by a small engine mechanic.

About the Author


Michael Rippetoe has been writing for 15 years, and has recently decided to make it his career. He has been a journeyman carpenter, ASE Master Mechanic, certified irrigation professional and currently writes for this site, designs websites, and does professional photography. Rippetoe's articles appear on eHow, Garden Guides, AnswerBag and others.