Stihl love/hate MS251C

[Hammermechanicman]

I have a 361 clone and a 660 clone both running 195psi compression. If you don't use the compression release it breaks the starter pawls. Over 10:1 compression ratio. Dozens of tanks of regular gas through both.
I have always wondered what the failure mode of 2 strokes is when a fuel with too low an octane rating is used.

 

[RaulMcCai]

Will have some effect ot starting, but also need to take into account that older saws ran a 7:1 or so compression ratio whereas the newer Stihls, Husqvarna, Dolmar/Makita run a 10:1 ratio. Which is the reason that call for 89 octane or higher fuel.

do you know when this happened? when the switch for Stihl specifically occurred?

 

[ILENGINE]

do you know when this happened? when the switch for Stihl specifically occurred?

Don't know specifically but I purchased a new 029 around 1995 that called for 89 octane or higher. Picked up an old 015 at a pawn shop in the late 80's that ran on 40:1.