Chainsaw Repair

I normally fun 40 to 1 with uncut fuel as not blended. 91 oct is the gas I can find. Plus I need to run the same fuel in my 550xp. Would I be ok with what I have already 40to1 91oct. Would that be ok or all my saws. Or could I run aviation fuel 100 oct with low low lead.. The only thing is my 550xp . Manual says no lead. So what should I do


Please let me know..

Thanks
Jason

               Your 40:1 is fine, as long as your saws are tuned to it. I have a 288 and a early 262.  Love them both.  As for the   550, if it is still under warrentee, than run what they recomend till it runs out, just to be safe.  The best combination that works for me is; Non-eythnol 89-92 oct. with Stihl Ultra oil mix.   This has been "good" up to 6-months or more for me.  Any longer than that it goes in the tractor.    If you use eythnol laced gas, figure 1-2 months at most with the Ultra in it.  Just make sure you tune the carb. to the mix ratio. Enjoy 

My guess would be 100ll will be ultra safe fuel, along with making less power then 91 octane. There is not enough compression and timing in a stock engine to use the advantages of high octane.

I see no reason to not use 50:1 in them all - but I use only the Aspen premixed alkylat fuel that Husky etc. sells.

The oil lubricating demands are different for a liquid cooled  snowmobile engine then a air cooled chainsaw powerhead.