Oil Question, "more than likely many times" for most of you!

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WeldrDave

Feeling the Heat
Nov 14, 2012
460
New Jersey
Ok all,
Please don't throw stones, but I would like to get the opinion from all the guy's, or ladies who have torn the
saw's apart and seen whats going on inside. I don't want to get long winded but:rolleyes:... My old 021 stihl has been running steller since 1989, after buying a POS 390 with the piston fried, it got me thinking, maybe I should look at my 021 piston. so I pulled the muffler and the piston looks like the day it was new, even has the milling marks still on it!!!! Now, I work with metals every day, I've looked at the oil shears, thermal breakdowns, viscosity levels, TC-3, air cooled oils, blah, blah, blah....... For the longest time, "not even giving it a thought" I ran Johnson outboard oil in my saw until recently. The old girl, 021 "STILL" runs like a ***** ape;ex... My question to all of you is, What's your experience;? do you use full synthetic, part, conventional, etc.... I have been using pennzoil air cooled 2 stroke and johnson 2 stroke in the leaf blower and weed whacker for years! When I bought my new MS250. I have "only" been using the ultra Stihl oil due to the warranty. Now, I have a 24 year old 021, I've been using every year since new, with various oils, "BUT I HAVE BEEN TRUE" to the mixture, Is there that much difference ? Thoughts please, I would like to understand this more. Thanks gang:)
 
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They say it will not lube as well at the high temp of air cooled stuff. I use husky oil in my air stuff. At 40:1. When I pulled 390 down after 7 yra it looked new to me!
 
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so I pulled the muffler and the piston looks like the day it was new, even has the milling marks still on it!!!

This may mean less than you think; the milling marks on the pistons I've looked at are pretty deep to begin with.

The fried piston on the 039 will have been due to some air leak, or carb maladjustment, or running straight gas. I doubt that any negative effects of a less-than-optimal oil would be so dramatic.
 
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