I have a customer who has destroyed 2 310's. The piston and cyl. are scored on the ex. side on both saws. I know this guy, and how he takes care of his equipment, and it most likley isnt him. Same gas has been used in 2 other saws...90+ octane, minimal alcohol. Pressure and vac. tested, tight as a drum. No obstructions in the muffler and fuel line, filter and carb is in good shape. One of the 310's was 15 months old and the other is about a month. He has been running Stihl oil, and when I checked there was nothing but premix in the fuel tanks. I'm scratching my head, any thoughts would be appreciated.
Jim
Jim