That piston is roasted. You should've removed the cylinder before carving anything, and then made sure there were no shavings left before putting it back on. That's unfortunate, I hope you find a good deal on a cylinder and piston kit.
Someone please tell me I didn't burn a piston
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Thread summary:
Clearly, I did indeed burn the piston. The saw is making it's way across the country for a hopefully better life elsewhere.
Possible causes, in approximate order of likelihood:
1) I attempted to adjust the carb high setting, starting too far off the correct mark. Resulted in running too long at WOT to find the rich spot. => lean seize
2) Air leak near the spark plug (as later diagnosed by the dealer) caused the lean seize.
3) My woods port, which also introduced a new spark screen, may have scavenged in debris, most likely from the screen which didn't hold up. The actual grinding to enlarge the exhaust port was done cleanly, so highly unlikely that debris came from that. The screen actually broke though, so possible debris from the screen.
4) Due to the unknown history of the saw, there could have been any number of other possible issues with the saw. Possible a fuel line somewhere in or out of the carb. Possible issue with the bearing. Just before I bought it, the flywheel and piston had been replaced.
So, unfortunately, it's impossible to say for sure what happened, and whether I made a bad purchase or whether I screwed it up myself. I'm going to assume that both are true. Too many questions for me to pursue it any further. That's why it's moved on to someone braver/smarter than myself. Expensive lesson, kids!
Clearly, I did indeed burn the piston. The saw is making it's way across the country for a hopefully better life elsewhere.
Possible causes, in approximate order of likelihood:
1) I attempted to adjust the carb high setting, starting too far off the correct mark. Resulted in running too long at WOT to find the rich spot. => lean seize
2) Air leak near the spark plug (as later diagnosed by the dealer) caused the lean seize.
3) My woods port, which also introduced a new spark screen, may have scavenged in debris, most likely from the screen which didn't hold up. The actual grinding to enlarge the exhaust port was done cleanly, so highly unlikely that debris came from that. The screen actually broke though, so possible debris from the screen.
4) Due to the unknown history of the saw, there could have been any number of other possible issues with the saw. Possible a fuel line somewhere in or out of the carb. Possible issue with the bearing. Just before I bought it, the flywheel and piston had been replaced.
So, unfortunately, it's impossible to say for sure what happened, and whether I made a bad purchase or whether I screwed it up myself. I'm going to assume that both are true. Too many questions for me to pursue it any further. That's why it's moved on to someone braver/smarter than myself. Expensive lesson, kids!
I was able to purchase this saw from the OP. With his permission I am updating this post with my progress on this rebuild. I received the saw today and only had 15 min to look it over before having to head to work. The piston is junk and the cylinder is in rough shape. Exhaust side is much worse than intake.
The bearings are shot, tight but very rough. Inside the crank case looks like it had debris rattling around inside as it appears there are many "impact marks"
The saw came to me partially disassembled but according to the notes from the dealer the OP visited it had several air leaks including around the spark plug. Threads look to be in good condition.
I plan to split the case and replace the bearings, clean up the cylinder ala mastermind tutorial (hopefully), helicoil the plug hole if need be, new OEM piston. Repair any other issues along the way.
Hard to say what caused this issue, my gut feeling is the OP purchased this saw in its current state or close to it. Multiple air leaks and bearing pieces flying around in the case would certainly explain it more than running it once for 30 seconds after doing a muffler mod. There are definite honing scratches on the cylinder and it has had the flywheel replaced. Not sure why but may find more clues as I delve in. Any thoughts, comments, opinions welcome.
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The bearings are shot, tight but very rough. Inside the crank case looks like it had debris rattling around inside as it appears there are many "impact marks"
The saw came to me partially disassembled but according to the notes from the dealer the OP visited it had several air leaks including around the spark plug. Threads look to be in good condition.
I plan to split the case and replace the bearings, clean up the cylinder ala mastermind tutorial (hopefully), helicoil the plug hole if need be, new OEM piston. Repair any other issues along the way.
Hard to say what caused this issue, my gut feeling is the OP purchased this saw in its current state or close to it. Multiple air leaks and bearing pieces flying around in the case would certainly explain it more than running it once for 30 seconds after doing a muffler mod. There are definite honing scratches on the cylinder and it has had the flywheel replaced. Not sure why but may find more clues as I delve in. Any thoughts, comments, opinions welcome.
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Probably all over the cylinder walls but we'll see. Trying to decide what to do about the case. Leave it as is? Should I worry about paint flaking off? Never had one this chewed up before.
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