If it is a 2-cycle engine, replace 25 % of the 2-cycle oil with Marvel Mystery Oil. For example, if you normally use 8 ouces of 2-cycle oil, use only 6 ounces of 2-cycle oil and 2 ounces of Marvel Mystery Oil. For 4-cycle engine, use 1 ounce of Marvel Mystery Oil for each 2.5 gallons of gasoline.