Chainsaw Repair

Husqvarna - Stihl - Poulan - Jonsered - Dolmar chainsaws and more => McCulloch => Topic started by: SlocanRiverMan on December 15, 2016, 03:34:30 pm

Title: ProMac 55 will not start
Post by: SlocanRiverMan on December 15, 2016, 03:34:30 pm
Newbie to this forum. Got a Pro-Mac 55 that my wife bought for me back in 1976 and cannot get it started. Swapped out carb, spark plug and fuel system from a friends working unit, put in new gas. Spark looks good but still not starting and not even a burp to get my hopes up.  Bought a Stihl pro saw but would still like to get the Mac back on the road. Any ideas would be much appreciated. Thanks.
Title: Re: ProMac 55 will not start
Post by: pete on December 16, 2016, 01:27:30 am
just an idea but had this with a 10 10 that came into my collection recently spark but no go take the plug out check yep spark but still no go. purely by chance as I put the plug back in for about the 5th time I got a fart  any way removed the starter cover this is a LH start unit and found a spot where the plug wire had worn through and was earthing out on the body. Every time plug was out it cleared the body as I screwed it back in and reconnected it the wire touched to ground so its worth a try
Title: Re: ProMac 55 will not start
Post by: Al Smith on December 16, 2016, 04:30:14 am
That Mac is old enough it could have a break in the fuel like ,could be inside of the tank .Give it a shot of fuel through the carb and pull the rope .If after a while it doesn't fire then most likely it's a spark problem .

 For the most part McCulloch coils are pretty robust ,I've only seen two faulty ones .One of those actually worked some time later when I tested it .Whatever was wrong with it healed itself and remains a mystery to me .
Title: Re: ProMac 55 will not start
Post by: SlocanRiverMan on December 16, 2016, 11:17:27 am
Thanks, good idea, I will try that plug wire thing, never thought of that.
Title: Re: ProMac 55 will not start
Post by: SlocanRiverMan on December 16, 2016, 11:22:53 am
Thank you, I had swapped out the entire fuel system, lines, filter and all,  from a friends working unit and it still didn't start. Had a fellow mention a worn through plug wire that ONLY shorted out when the spark plug was screwed in and the plug wire attached. Will try that.
Title: Re: ProMac 55 will not start
Post by: fossil on December 19, 2016, 11:47:05 am
Any idea what the compression is on the saw?
Title: Re: ProMac 55 will not start
Post by: SlocanRiverMan on December 19, 2016, 12:35:38 pm
No, I haven't checked the compression. Will try that as well. Thanks.
Title: Re: ProMac 55 will not start
Post by: SlocanRiverMan on December 21, 2016, 11:55:58 pm
Checked compression and after about 6 pulls it only came up to about 35-40 psi. What should be normal compression?
How do you reply to another persons post? Not sure I'm doing it right.
Title: Re: ProMac 55 will not start
Post by: pete on December 22, 2016, 07:07:13 am
before you pull it down try another compression tester then drop the muffler and shine a torch in and check piston and cylinder for scoring  if that looks clean and compression is low with another tester sounds like rings are in order