Did I tell the chain saw story?
Last week, I needed to start my small 024 Stihl. Almost no compression, barely fired...but since it did fire, I knew it had spark.
After playing with it for an hour...trying all my tricks, Seafoam in gas, starting fluid in carb, starting fluid in cylinder...BTW the spark plug was extremely carboned up, I don't think anymore corbon could get in there. I "think" I have only swapped plugs one time in 20 years with this saw? This saw doesn't get the majority of use. I did try a new plug that day, no luck.
I get my "backup" 024 out (that I bought out of a junk pile and got it running 2 decades ago), I know it hadn't been started for 15 years, put fresh gas/mix and it fired right up and got my small logs cut. As I used it, I remembered it leaked gas and bar oil. Hairline crack in gas tank, rough finish on bar oil fill hole. That's why it's a backup and never gets used. I do recall setting it up with a safety chain, in case I ever had a friend want to borrow a saw. also that day, I made a couple slab cuts (rip) in the sugar maple log with crotch, dang that safety chain works well for that, I will bank that knowledge for future use.
Back to the 024 with little compression. I'm thinking it's junk. I tell the story above to all my friends. They all mentioned gas...we all know what gas to use, I said, LOL. My friend with the most experience with saws and engines asked about my use of the saw previous to last week. I told him I was slabbing a bunch of logs for turning on the lathe. He asked how long does it take to make the cut? I said about 4 or 5 minutes. He asked if I give the saw a break? I said, of course not. So he says, it's probably shot, you ran it too hard, too long, probably got too hot. BUT, he said, maybe, since the plug was so full of crud/carbon, maybe the ring was full of crud/carbon also, then the hot running cooked that crud and "stuck" the ring.
So, I take his advice of pouring some seafoam into the cylinder and let it sit overnight. Well dang, the next morning, the saw had good compression, I guess the ring became unstuck? I didn't try to start it, I just pulled the cord to check, as I didn't have time give it a good cleanup.
Sunday morning (3 days later), I remove the muffler, clean the muffler screen and inspect the cylinder/ring via the exhaust port as another buddy suggested. Dang, the piston and ring looked fine, no scratches and no carbon along the ring, or anything. After the cleanup, I put some fresh gas in, and it fired right up, ran as good as ever, maybe even better.