The Ryobi gas trimmer uses a fuel mixture with a ratio of 32:1 to power the engine. The 32:1 ratio is a mix of unleaded fuel with two-cycle engine oil. It is a good idea to keep a gas can set aside strictly for fueling your gas trimmer. This will prevent accidentally placing straight fuel into your trimmer and damaging the engine. Most trimmer malfunctions are a direct result of improperly mixed fuel in the engine.
Use a clean 1-gallon gas can specifically for fueling your Ryobi gas trimmer.
Pour a 4-ounce can of two-cycle engine oil into the clean gas can.
Pour 1 gallon of unleaded gasoline into the gas can.
Close the gas can lid and swirl the fuel mixture around to thoroughly mix the fuel in the can.
Pour a fuel stabilizer into the fuel mixture if the gasoline you are using is a blended gas. Ryobi recommends using STA-BIL as a fuel stabilizer for the fuel mix. Use the stabilizer according to the instructions on the can.