New onwer of Stihl 031AV...having little problem

[EricM]

Hello all, I'm new to chainsaws and I just bought an 031AV (not sure what year) and I cut with it yesterday. Very happy with it so far, but the chain won't stay tight. I'm guessing it's the tensioner???

When I first started using it, the chain would stop when sitting at idle. But now, not so much. It runs at idle. So, I'm not sure if it's the clutch or the tensioner. I've fiddled with it for the past hour and can't get it to stay tight.

So far I've taken the side cover off, inspected, made sure the bar was on the studs properly before tightening, lifted up and out on the bar when tightening the nuts. As soon as I start it up it's not staying tight and goes back to too much slack in the chain.

If bad tensioner, how difficult is it to replace? What manual to get? Service/repair, owner's manual, parts breakdown? I don't even know how this thing in engineered, could the clutch even be bad and causing this?

Thanks

 

[cbfarmall]

Once you crank the bar nuts tight, the tensioner's job is finished. The clamping from the nuts holds the bar tight not the tensioner. In any case, as long as the adjuster is turning freely, travels the entire length of the slot, and isn't bent up, it is OK. To change it, you would have to unscrew both bar studs, not something to be done lightly.

Generally what causes a loose chain that fast is a very wore sprocket. Look at where the chain engages the clutch drum and you ought to see wear. A new chain on a old, wore out sprocket will quickly result in a wore chain due to pitch mismatch.

You could have a bent crank, but that would cause an alternating loose/tight chain and a bunch of other problems. Crank the saw over slowly and watch the end of the crank for runout.

The bar studs could be loose in the case, causing the bar to come unclamped.

If you feel the saw is worth it, I'd invest in a new bar/chain/sprocket.

Good luck and post back your findings.

Chris B.

 

[cbfarmall]

BTW, go to stihlusa.com for a free copy of the owner's manual or find it on Ebay. It will tell you everything you need to know to remove the clutch, inspect the sprocket, and everything else you need to know for your new saw.

Chris B.

 

[sloch24]

Hmm..

I'm going to state the obvious here, so excuse me if I'm wrong, but....


On the older Stihl chansaws, the chain tensioner was next to the bar (almost too damn close to the bar). Did you use the tensioner when you installed the bar and chain? The reason I ask is that you stated that you lift up and "out" on the bar when you tighten the nuts. Nobody is strong enough to get the correct tension on the chain just by doing that. Also, is the bar making good contact to the tensioner? I've seen people tighten the bar to the saw and actually break the end off of the tensioner. If that was the case, the tensioner would do nothing.

 

[sloch24]

Oh yeah...

Welcome to AS!

PM (Personal Message) me your email and I'll send you the IPL and owners manual. They are available on the Stihl website, and if you want a printed copy they will mail you one as well (photo copy).

 

[cbfarmall]

Did you use the tensioner when you installed the bar and chain?

Hmmm.... I took it for granted that he was adjusting the tensioner for the B/C. But now that I reread his statement, I may have assumed too much.

First saw I ever used, a crappy little electric saw, I could never get the chain tight. I just loosened the bar nut, pulled the bar out by hand, and retightened. I wrestled with it for quite awhile before I took off the bar cover and figured out that it had a tensioner. Still have that saw, just as a reminder.

Live and learn.

Chris B.