OK, guys...Uncle Sam doesn't allow me to purchase any fuel other than regular...it's considered an unnecessary expense, not required by automotive manufacturers. So if I wanted to purchase premium for my saws, or ATVs, or snowmobiles, I have to go through hoops only a saint could endure.
So I've run nothing but 87 octane fuel in my chainsaws since forever. And we have 10% ethenol here.
Zero problems, none, nada.
Y'all do run saws many more hours per month than I do, but my saws might sit with fuel in them for weeks at a time between being run, and my dolmar might have mix in it for several months before being refilled. I think my fuel usage must be worse for saws than most folks...but I have no problems, in many years of this sort of mistreatment.
I draw no conclusion, only pass this along for consideration.