MAG58
ArboristSite Guru
I believe you are on the trace of something, regular gas is 95 octane, and Premium is 98 octane here, 92 octane is availiable at a few stations, but not usual at all.
The old Jreds 621 "calls" for 1:25, but has been run on 1:50 Aspen Alky/Synthetic Gas/Oil premix for lots of years, with no apparent ill effects....
A friend of me have one old Jonsered that he use and abuse, and he run 50:1
:greenchainsaw: