Stihl MS261-C chain tightening

KWood255 · October 25, 2022, 07:28:25 PM

Hi folks, among my collection of saws is a MS261-C, which I bought new about 5 years ago. The saw has seen some use, but not extensive in comparison to other saws I have.

Recently, the chain began tightening all by itself, to the point that it would nearly stall the saw. I've taken it apart a few times to clean and inspect, changed the bar and chain...no luck. It seems to occur within a couple minutes of use.

I've tried tightening the bar cover nuts heavily, and to spec. No change. Bar oil consumption seems consistent. No obvious damage to the tensioner etc. I'm stumped, and getting frustrated with this saw. Any suggestions? Thanks in advance. I appreciate the feedback.

lxskllr · October 25, 2022, 07:38:04 PM

I don't know much of anything, but I'd look around the sprocket and crank for play. As a test, I'd put the chain on, but leave it a little slacker than you normally do to give the bar plenty of room to move if it's going to. Pencil a line on the bar, then do some straightforward bucking cuts. See if it tightens up. If it does, check the mark you made on the bar to see if it moved.

Old Greenhorn · October 25, 2022, 08:40:53 PM

Kwood, what is your process for tightening your chain/bar? DO you set the saw on a stump or bench, tension it until it looks right, then tighten? If so, this is where your issue is. You need to set the chain tension with some pressure on the tip of the bar pushing up. In other words, lift on the back handle so that the nose is on the bench and THEN set the tension and tighten the bar. Otherwise you have the bar tight, but cutting pressures let it slip up and that overtightens the chain as you cut.
It's happened to ~~all~~ most of us.

KWood255 · October 29, 2022, 08:23:41 AM

Quote from: Old Greenhorn on October 25, 2022, 08:40:53 PM
Kwood, what is your process for tightening your chain/bar? DO you set the saw on a stump or bench, tension it until it looks right, then tighten? If so, this is where your issue is. You need to set the chain tension with some pressure on the tip of the bar pushing up. In other words, lift on the back handle so that the nose is on the bench and THEN set the tension and tighten the bar. Otherwise you have the bar tight, but cutting pressures let it slip up and that overtightens the chain as you cut.
It's happened to ~~all~~ most of us.

Thanks very much. I will try that and report back. It was never an issue until recently. I've ran a hundred or more tanks of fuel through this saw, without any issues previously. Perhaps she's getting a bit worn.