Braved the cold the other night and did a little carbon cleanup on the one owner 4200 I got recently. Had quite a bit of carbon build up inside the muffler and by the exhaust port. Scraped the inside of the muffler with a flat head screw drive and blew it all out with the air compressor. Here are a couple pics of the piston, one dark area but all looks good. Compression is right about 155 and it idles and accelerates great.
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View attachment 466784
Sounds good to me Nate! 155 lbs. From what I have seen, 150-160 seems to be the norm. Might see one a little higher occasionally. Wire wheel on a drill always worked good for me cleaning up muffler parts. They are fairly easy saws to hear the transition from rich to lean when in the wood, when setting the high end. I have more trouble hearing that on saws like the 3400-4000.
Gregg,