Why is fuel mixing with engine oil in the crankcase?

If you notice gas mixed in with your engine oil, follow these instructions to address a potential leak.

• The fuel shut-off valve isn’t closed properly.
• Fuel float in the carburetor being stuck in the open position due to gumming (caused by stale fuel) or debris.

• If your engine has a fuel shut-off valve, ensure that this valve is closed when the engine is not in use.
• If carburetor problems are causing fuel to mix with your oil in the crankcase, you should perform a thorough cleaning. Find out how to clean your small engine carburetor.

For any other specific questions or concerns related to fuel and oil, make sure to contact a Briggs & Stratton Dealer near you. You can also find carburetor cleaner, lawn mower oil and more service materials in our online store.