That sounds like lack of compression. My rule is that if they have less than 110 lb compression, they are history and not really worth rebuilding. Save it for parts if another one comes along. One time I tried rebuilding one and while tightening the cylinder mounting bolts I heard a crack! The party was over. and that's the last time I ever tried to rebuild one.I have a 4218 that I can’t get running at all. Can get it to fire but it’s can’t get it tuned to stay running and eventually I can’t restart it. I’m gonna give it one more go and then done with it. Pissed I threw money at it but i think it may have a bad seal or something. Only saw I’ve not been able to get running.
The other “cheap” polyandry I’ve had have all been simple. Something with the 4218 though...
I've run into that also. Fuel line problems are the #1 thing that gives up on these saws, and of course they use a fuel line size that nobody seems to carry. The connection to the tank is usually just a drilled hole. Sometimes I enlarge that to fit the line that I have. And, of course, the primer bulbs either crack or fall apart on a regular basis.Another common issue is the inner part of the stupid ass double wall fuel line collapses. Then you need to replumb it. I have one that wouldn’t even purge because the line was collapsed right above the fuel filter.
Is that a stratosaw?You guys might get a kick out of this. An owner of a Craftsman 4218 could not start it and actually broke the handle off the cord trying to get it running. He said to me, "Edwin it's all yours, I'm through with it." Then he walked away.
I discovered a loose spark plug that I tightened. Then I re-attached the handle:
View attachment 858709
The saw starts and runs perfectly today and has hardly a scratch on it. Thanks for looking.