Hi folks, thought I'd ask the pro's on this, I bought an old Mac 10-10 a few months ago on an estate auction. I knew the owner well so I knew it would run fine, paid a whopping $3 for it and it started on the third pull, didn't even have to put fuel or oil in it, my trouble is after a few revs the chain tightens enough to stall the clutch. The tensioner screw was gone so I got one from sponsor Chainsawr (very good service by the way) but it still does it, I can't find anything else out of place, the saw starts, idols, and runs good so I'd like to be able to use it. Any help is appreciated, thanks in advance.
Not sure if this saw is manual/auto on the chain lube or just manual. Could be the chain running dry. When adjusting tension they say you should hold the tip of the bar up and then you adjust it, then tighten it down. You should then be able to pick the chain up a little. Say enough so the bottom of the driver is almost even with the top of the bar. You need them snug not caterpillar tight. The chain or drivers could also be the wrong gauge for the bar. Say the drivers are .058 and the bar slot is .050. Just an example. Other than that my brain is on shut down this morning. lol
Thanks HiTech, I've adjusted this thing with tip both up and down, snug, loose, you name it, the bar and chain are new (they came together). The only other thing I can think of is the drive sprocket which looks to be alright? everything thing else seems good and tight, the bar and chain that were on the saw when I bought it did the same thing right from the start. Guess worst case scenario I'm out of three bucks and will have to buy a different saw the new bar and chain will fit on :D.
Sounds like the wrong pitch chain for the sprocket.
John
Make sure the pitch of the chain, bar sprocket, and drive sprocket all match. Also make sure the tension adjustment is staying where you put it, and your bar is staying tight once you tighten it down.
Thanks guys, oldguy that's what I'm thinking it must be, Donnerparty the bar and chain are Oregon and came as a set, that's why I'm leaning towards the drive. Since the original did the same (ruined the bar) I don't think there's any problem with the bar and chain? When I can get to it I'll let you know how it turns out, thanks again.
This issue has been addressed on here before but DanGed if I can remember anything about it, nor can I find the post.
There's two primary causes of the issue the OP referenced. One has been addressed. And that is an incorrect bar/chain/sprocket combo.
The gauge, pitch of the bar sprocket (if equipped) and the pitch of the saw's drive sprocket all have to be correct.
The other common cause of this is a badly worn drive sprocket. The chain drivers fit down into the badly worn groove in the sprocket some of the time and the other times they come out of the groove onto the unworn part of the sprocket. This will cause the chain to either tighten or loosen depending on where the chain was riding when it was tensioned.
Howdy,
Yes, check the sprocket. Mac used to make .354 pitch, and it looks a lot like .375. The sprocket can peen the drivers which makes them wider, and start hanging in the bar groove.
Regards
Gregg
If it is .354 which is rare is doesn't take much to change the drive system .You can opt for a sprocket drive ,rim drive or a contraption they made that is in essence a rim welded to the clutch drum for whatever bright idea that was.You got to remember it's a McCulloch and they changed their ideas about every full moon .
Quote from: deerslayer on January 15, 2016, 02:41:17 PM
There's two primary causes of the issue the OP referenced. One has been addressed. And that is an incorrect bar/chain/sprocket combo.
The gauge, pitch of the bar sprocket (if equipped) and the pitch of the saw's drive sprocket all have to be correct.
The other common cause of this is a badly worn drive sprocket. The chain drivers fit down into the badly worn groove in the sprocket some of the time and the other times they come out of the groove onto the unworn part of the sprocket. This will cause the chain to either tighten or loosen depending on where the chain was riding when it was tensioned.
Yep, a new drive sprocket fixed mine.
Thanks very much everyone, I'll try a new drive first chance to get one.