Most older engines ran at 16:1, then 25:1, then 32:1, then 50:1, and some now claim 100:1... advances in engine materials, and more willingness to sacrafice engine life to make some (censored) california smog people happy in their crusade against lawn care. Too much oil won't hurt the engine, so if you don't know the correct ratio, err on the side of too much oil. I stick with a 16:1 mixture in everything, as that's what my old saw takes, and I'm not about to have different cans of gas for each 2-stroke engine...
--Bushytails