high compression


Old 04-21-03, 07:55 PM
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Unhappy high compression

I am working on a McColloch chainsaw. It is a Promac 440. I got it from my father since it had not been working for many years. The most immediate problem is The compression seems way to high to start. I can't even pull the start rope without lifting the saw off the ground. If I take out the plug, it spins over super easy. I stripped it down to the bare bones hoping to find something. No luck. Is there some compression release mechanism that isn't working? I even pulled off the head. Everything looked ok. Is the gap in the piston rings supposed to be in a certain position? Any help or advice would be greatly appreciated.
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Old 04-21-03, 08:06 PM
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I am not familiar with your saw offhand, but I don't believe it has a compression release. Some of these have a lot of compression, and are hard to start. Make sure the flywheel is not loose on the crankshaft, or out of round and hitting the coil legs.
Old 04-22-03, 05:39 PM
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You were right. I guess high compression is normal with this saw. I put everything back together, cleaned the carb., replaced fuel lines, put fresh gas in with a good synthetic oil, and it started for me. What I did was pull the starter rope many times with the spark plug out to get the fuel worked through the lines, then reinstalled the plug and it fired up after a few pulls.
Sounds pretty good to me, only idles way to high. I will go thru the forum to find out how to adjust. Thanks for your help!! This is a great forum for the doityourselfer!!!!!!!!!

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