At the time that Homelite was making these trimmers, Homelite was running a 32:1 ratio in their trimmers and saws. As far as I know, Homelite never ran a 40:1, and only the newer items are 50:1. What most people don't know, is back when saws where 16:1 that was before the Use of 2 stroke oil as we know it. It was a mixture of 8 ounces of 30 W non-detergent motor oil, to a gallon of gas.