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661 Oil Test 32:1 vs 40:1 vs 50:1 ?



Addicted to ArboristSite
Oct 9, 2013
***EDIT - Test completed...jump to page 15. http://www.arboristsite.com/communi...1-vs-40-1-vs-50-1.276534/page-15#post-5300597

Looking for some opinions on a test I'm going to do, hopefully this saturday.

Test - mix up 32:1 40:1 and 50:1 with stihl utlra and 92 oct eth free. Start off with 50:1 and do a couple of timed test cuts then take the jug temp with the thermo gun. Then empty the saw and refill and run 40:1 for a bit to get the mtronic doing it's thing with 40:1, then do couple of timed test cuts and take jug temp and repeat same process with 32:1.

Saw - 661R.
Bar - 36" tsumura
Chain - that is the question - I can run either 3/8 or .404. new Stihl RS.

3/8 - pretty much everyone uses that but..
404 - seems to me 404 would require more power and it seems to me that if there was THAT much difference the 404 would make the saw and mix show it better.

So what do you guys think?
NIP Group
Natty Bumppo

Natty Bumppo

ArboristSite Operative
Dec 10, 2012
I wouldn't expect enough of an improvement or liability to make a difference in cutting speed by changing gas/oil ratios in that range. I thought most of us went with 40:1 or 32:1 rather than the manufacturer's recommended 50:1 for better lubrication and engine protection.
Of course, I could be wrong.
Oh, and go with .404