Then on a whim I bought a bottle of amsoil and ran a tank at 80:1, seemed fine, thin oil. I wanted to believe in the magic of 100:1, I can't explain why I feel silly in retrospect. So I mix up a gallon at 100:1. Still not really working the saw too hard. Except for slabbing of the side of a 12" birch. Ran it wide open for several minutes. And then I was messing with the high idle and like and idiot using my cellphone to try and tune the sucker. I usually tune by ear but I had both ear plugs and music earmuffs going. (muffler ported) I knew the phone was giving bad readings and I increased the high idle speed too much. Kapow, she sized hard, metal shavings coming out the exhaust etc.