some folks come on these oil threads and complain. If it was so painful to keep rehashing this stuff, why not just ignore them?
My opinion on Amsoil @ 100:1 (or opti II, et al): Ok in cheap dept store string trimmers and saws, marginal in dept store blowers, and not for me in quality equipment , especially when used hard. Here's why I believe this:
As engine speeds and air movement through the engine increases, less and less oil will stay puddled up in the crankcase. That green weedeater with ports the size of a pencil just cant possibly move enough air through to keep all of the oil in motion, while your average 50cc saw running at 13,000 rpm, Wide open throttle, is not only whipping up all the oil laying in the crankcase, but is making 2 or 3 times as much heat.
Amzoil amd the rest are banking on the fact that only a few saws and only a few users will use their stuff that hard, and even so, their equipment will hang together (but not thrive) long enough that they can usually deny culpability when the tools meet early failure. As, for example, Andy's Stihl photo.
For the record, I think Amzoil is a great product, but it isn't magic. Works spectacularly at 50:1 in chain saws. But so do a lot of others. Most of Amzoil's business model is servicing fleet users, farms, factories, etc., with a smaller slice servicing the rest of us. If you know someone that has an Amzoil account, Amzoil is a great deal, but for the rest of us, its a little like Rainbow or Kirby vacuum cleaners: tons of hype and markup.