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40:1 in an MS261C-M??

kennyz

kennyz

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I just picked up an MS261C-M. So the service manager comes out with it after firing it up and making sure it was all set. I mention to him that a lot of guys recommend running it at 40:1 and he freaks out. " Don`t do that unless you want to destroy the saw" he says. What are your thoughts? What possible harm can it do? Obviously Stihl sticks by it`s recommendation of using 50:1.:confused:
 
Kenskip1

Kenskip1

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Tell the service manager to go fly a kite. 40-1 will not hurt your saw.For a brand new saw I was using 32-1 but 40 is fine. Should not have any problems. 50-1 is the bare minimum.40 is just that little bit of insurance.
 
Justin Taylor

Justin Taylor

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The only reason why 50-1 is a thing is for epa regulation but yes 40-1 is just fine and that’s what I run but I haven’t seen anything bad when people do run 50-1 on stock saws
 
Ryan'smilling

Ryan'smilling

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I've run 40:1 exclusively in my 261 since new. No problems.

I will say that I've heard of problems running a thick mix (32:1+) in small saws with low loads, like for limbing. I think it's an issue with some oils and not others. Some guys run oils designed for 2-stroke racing and extreme loads. If you mix an oil like that at a high ratio and then don't get the saw hot enough long enough, you won't achieve combustion and you'll get carbon buildup. I wouldn't worry about running 32:1 in a 70+cc saw for long bucking cuts, but I'd stick to 40-50:1 in small saws in a limbing situation.
 
Trail Blazer

Trail Blazer

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I split the difference and go approx. 45:1 or maybe slightly richer, but typically never any leaner than that. 372 XP, Husky 460, MS 250, and FS91 all seem to run well on that mix. I just figured a little rich is certainly better than a little lean.
 
CR888

CR888

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Going by some arbitrary number for oil ratios makes little sense as 2T oils vary greatly in viscosity depending on what they are. You may have more oil @50:1 than 40:1 depending on the oils. This is where folks run into trouble, they'll here 32:1 is a great ratio & mix up some heavy duty high load, maximum protection bike oil up and wonder why their saw won't idle or run well. What I'm saying is 'how much' oil depends greatly on 'what' oil you intend to use & in what application you intend using it.
 
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