Lucas Oil Fuel Stabilizer is safe to use in all grades of gasoline and in all 2 and 4-cycle engines. It is a great solution to prevent gasoline break-down during storage and is easy to use. A better solution to prevent gasoline break-down during storage. Safe to use in all grades of gasoline and in all 2 and 4-cycle engines. Easy to use!. Application rate, 1 ounce to treat 1 gallon.