How to Choose Fuel for your Mower
Learn what the best choice of fuel is for your mower and outdoor power equipment to avoid poor engine starting and performance.
For the best engine performance, you always should use fresh, clean gasoline. Gasoline begins to degrade in as little as 30 days which can cause gumming and varnishing of your engine’s fuel system. When your fuel system is clogged it leads to your engine not starting and costly repairs.
A minimum 87 octane containing up to 10% ethanol is recommended. Do not use fuels with 15 to 85% ethanol, these fuels are not approved for use in small engines. Mixing oil with gasoline or modifying your 4-Cycle small engine to run on alternative fuels will damage the engine and will not be covered under warranty.
At high altitudes, over 5,000 feet a minimum of 85 octane is recommended. To remain emissions compliant a high altitude adjustment is required. Operation without this adjustment will cause decreased engine performance, increased fuel consumption and increased emissions.
To keep fuel fresh add STA-BIL 360 Protection every time you fill your gas can. It stabilizes fuel up to 12 months and prevents corrosion caused by moisture in today’s ethanol-blended fuels. STA-BIL is America’s #1 fuel additive and is the official fuel treatment of all Briggs & Stratton engines. If gasoline in your engine is over 30 days old drain it into an approved container and run the engine until it stops from lack of fuel. Refill your engine’s fuel tank with treated fuel and run the engine for two minutes to circulate it through the fuel system.
