Stihl chain keeps coming loose

[Deleted member 168049]

Hi, Recently started using a chainsaw i bought 2nd hand. I tighten the chain correctly as many YouTube videos have shown me, however after about 5 minutes of use the chain is so loose it's comes off.

Does the tensioner need replacing?

- C

 

[HarleyT]

No, likely the sprocket, and thus, also the chain.

 

[HarleyT]

Put up some pics of the sprocket, and also the chain.

 

[Deleted member 168049]

Put up some pics of the sprocket, and also the chain.

 

[WPanhandler]

FWIW, I had a green branded homeowner chainsaw that,appeared too, but would not hold bar tight, so the chain would loosen. Turned out to be a “broken case.” Saw ran real good. If the above checks out good and saw is under warranty like mine was, You might consider Having that checked by somebody

 

[jp233]

Is this a Stihl 021, 023, 025 ? or MS181, MS211?

the sprocket is knackered. looks like the wrong chain has been used on it, in addition to heavy wear from normal use.

That's for a Picco chain (6 tooth sprocket). You need to verify what bar/chain is on it, and get a new sprocket to match (in case the bar/chain is usable). You may want a new washer, e-clip, and anything else in there depending on how hard the saw needs to be worked

 

[MacAttack]

I am 100% sure HarleyT will tell you that sprocket is smoked.

 

[CR888]

FWIW, I had a green branded homeowner chainsaw that,appeared too, but would not hold bar tight, so the chain would loosen. Turned out to be a “broken case.” Saw ran real good. If the above checks out good and saw is under warranty like mine was, You might consider Having that checked by somebody

I think the problem is evident in the pics.... sprocket is shot & needs replacing.

 

[jp233]

Yeah it looks like this sprocket below (link). Here's one in the UK for ya, in case you don't have a dealer nearby. If you have a Stihl dealer nearby, they probably have sprockets in stock. And they'd obviously have bar and chain if you need that too.

https://www.lsengineers.co.uk/chain-sprocket-for-stihl-ms171-ms181-ms210-ms230-ms250.html
You'll have to see if the chain drive links are rounded off and toast too. Sort it all out and it'll be fine.

 

[PV Hiker]

Show pictures of chain and bar and bar studs location. The bar will have marking on tail, show picture. What model is this saw?

Interesting that the wear is not centered on the sprocket.
.

 

[Deleted member 168049]

Yeah it looks like this sprocket below (link). Here's one in the UK for ya, in case you don't have a dealer nearby. If you have a Stihl dealer nearby, they probably have sprockets in stock. And they'd obviously have bar and chain if you need that too.

https://www.lsengineers.co.uk/chain-sprocket-for-stihl-ms171-ms181-ms210-ms230-ms250.html
You'll have to see if the chain drive links are rounded off and toast too. Sort it all out and it'll be fine.

That's very helpful, thanks
Chainsaw is a MS211
This is the bar
This is the chain
I've only just got the saw working from 2nd hand so none of this damage is mine, I'm sorting out someone else's mess. To add to the list of issues, the bar stud has eaten away at the body so i have ordered an overersized stud

 

[HarleyT]

Show us pics of the chain. You need to replace that also.

 

[Deleted member 168049]

Show us pics of the chain. You need to replace that also.

The chain and bar are 2 hours old, theyve only been on the saw 5 minutes

 

[HarleyT]

i have ordered an overersized stud

My wife calls me that...

 

[HarleyT]

Let us see the bottom side of the chain. There likely is some damage.

 

[Deleted member 168049]

My wife calls me that...

That's odd, whenever i ask she says

I think the problem is evident in the pics....

 

[PV Hiker]

The chain has come off you might have to look at the drive links for damage the chain won't fit in bar grove. A file will knock off the damage on the drive links.

Show pictures of your bar studs damage.

 

[Deleted member 168049]

Bar/chain pics

 

[Huskybill]

Time to get a rim and drum. Throw that sprocket away.

Check your chain adjuster make sure it’s snap ring that holds it inplace is there. I seen the bars loosen up if the snap ring is missig. The adjustment screw can come loose. You could have more than one problem.

 

[jp233]

yeah if the drive links got nicks and burrs in them, they need to be filed. the chain needs to swing freely on all links and not bind up. Also you will want to check the bar groove and make sure it didn't get dinged in the process of throwing the chain too.

Make sure that's a 3/8P chain and bar, and if so, and if the chain/bar is usable, a new sprocket should get you going. But bottom line is that sprocket is burnt toast.