The Forestry Forum
General Forestry => Chainsaws => Topic started by: mrcaptainbob on March 26, 2020, 10:45:18 PM
Here are
(https://forestryforum.com/gallery/albums/userpics/11825/IMG_5864.JPG?easyrotate_cache=1585276996)
(https://forestryforum.com/gallery/albums/userpics/11825/IMG_5863.JPG?easyrotate_cache=1585276986)
the two sides of the piston. The cylinder is the same way. Carb side smooth, exhaust side heavily scored. Both sides of the rings, including the rings.
What might have caused this?
Overheated. It was likely running too lean or insufficient oil. Could also be an intake air leak.
Hmm... don't think it was insufficient oil in the mix. I'm pretty judicious about that. It's only ever tasted Stihl mix and always at 50:1 with maybe a dribble more oil in the mix. Always.
So that leaves the lean issue or air leak. I checked the carb boot and it's air tight. Will check the other tubes and hoses and verify. I presume lung pressure is sufficient for air leak test...?
Could be mixture, that was too old.
A Mighty-Vac or similar tool is needed to pressure test, the pressure needs to hold.
The last couple times I used it there was evidence of a lot of 'splashing' from the muffler on the face of the wood being cut. Did not know it was blowing past the piston right out of the exhaust!