Small Engine Fuel and Gasoline Guide

If you purchase gasoline at the pump, check the labels to make sure it meets the requirements for your machine. Don’t buy more than you can use in 30 days. Pump gasoline that’s more than 30 days old can lead to corrosion in outdoor power equipment engines. The ethanol in pump gasoline can be another concern. It burns hotter and can wear out small engines more quickly than gasoline without ethanol. Know the level of ethanol your equipment can safely use. High levels can damage a small engine, resulting in machinery that won’t start. While you can find ethanol-free pump gasoline, most contains up to 10% ethanol.

Also, at the pump you’ll see different octane ratings, usually regular (87), midgrade (89 – 90) and premium (91 – 94). If you regularly maintain your equipment with fresh fuel and engine upkeep, regular octane gas will work in your small engine. Premium gas is designed for large vehicle motors and doesn’t improve fuel efficiency or performance in small motors that don’t require it. 

Most push and riding lawn mowers will run on pump gasoline. Smaller power equipment motors, like those in string trimmers, leaf blowers and chainsaws, are two-cycle engines that require a mixture of oil and gas.

Ethanol-free power equipment fuel from TruFuel and Husqvarna is available for four-cycle and two-cycle engines. It stays fresh, doesn’t degrade like pump gasoline does and provides dependable starts. Pre-mixed fuel for two-cycle engines also saves time by doing away with the need to mix gas and oil. It’s available in different gasoline-to-oil ratios, so you won’t need to measure and mix the fuel yourself. Pre-mixed and ethanol-free fuels are resealable and can last up to two years after first opening. Unopened, they can last up to five years, allowing you to stock up without worrying about loss of quality.

Fuel stabilizer helps protect outdoor power equipment engines. You can find stabilizers designed to prevent the formation of corrosion, gum and varnish and to treat fuel for storage. There are also stabilizers designed to treat ethanol fuel blends.

If you don't use a machine frequently or if you're preparing it for storage in the off season, you need to protect the engine. Remove the fuel by draining it into an approved container or running the engine until the fuel system is dry. Keeping the tank and fuel system full of gasoline treated with a fuel stabilizer is an alternative for some models — just follow the instructions in your manual.