Husqvarna 254xp - chain goes loose - help needed

[MartDalb]

Hi everyone

Got myself a fine Husqvarna 254xp - but after making it run well etc. I can't seem to figure out why the chain comes loose.

The rim sprocket is fine, almost brand new.
Chain is brand new.
Bar is...used but not worn out.
The chain tensioner system, screw, nut and rubber thingy is fine, threads aren't broken on the screw.
I tighten up the chain, and when I turn the chain by hand, is seems tight, at first, but turning it further more it seems loose and then tight again.
When I cut, the chain becomes loose, to a point where I have to retighten.

Any ideas?

 

[cscltd]

Your chain adj is in backwards.
screw head should be facing the other way

 

[HarleyT]

Why type of oil mix are you using?

 

[MartDalb]

Hi everyone

Got myself a fine Husqvarna 254xp - but after making it run well etc. I can't seem to figure out why the chain comes loose.

The rim sprocket is fine, almost brand new.
Chain is brand new.
Bar is...used but not worn out.
The chain tensioner system, screw, nut and rubber thingy is fine, threads aren't broken on the screw.
I tighten up the chain, and when I turn the chain by hand, is seems tight, at first, but turning it further more it seems loose and then tight again.
When I cut, the chain becomes loose, to a point where I have to retighten.

Any ideas?

Your chain adj is in backwards.
screw head should be facing the other way

Yeah, no that was just for the image sake, I took the chain adj. out to inspect and just put in on the saw.
The screw is backwards yes, but not when I run it etc of course.
Updated the picture. (and yes the rubber part that always goes bad will be replaced with a new one, but it was ok when running the saw/chain)
I have had a few adj. bolts threads go bad, so the screw would move around inside the "nut". But it seems completely fine this one.

 

[MartDalb]

Why type of oil mix are you using?

oil mix? I run Stihl or Husq premixed motomix or power.

 

[HumBurner]

Does the bar have any pinch to the rails?

I had one bar that had the tiniest pinch, barely noticeable without good lighting, and would push the tangs up and out of the groove before settling back in.


Also, verify that both rails on both sides are square and even. Also verify there is no debris jammed down in the groove.


Little things.

 

[MartDalb]

Does the bar have any pinch to the rails?

I had one bar that had the tiniest pinch, barely noticeable without good lighting, and would push the tangs up and out of the groove before settling back in.


Also, verify that both rails on both sides are square and even. Also verify there is no debris jammed down in the groove.


Little things.

I will recheck and perhaps find another bar, it is worn for sure.

 

[NSEric]

I had a bar with a worn out nose sprocket cause this.

 

[MartDalb]

I had a bar with a worn out nose sprocket cause this.

Sounds like I need to find a newer bar. I will check. I do have a Stihl .325 and chain, I could test with.

 

[HumBurner]

I had a bar with a worn out nose sprocket cause this.

Good call. All the more reason to run solid bars with replaceable tips.

 

[HarleyT]

oil mix? I run Stihl or Husq premixed motomix or power.

Why did you post a pic of the saw with the adjuster stuffed in the hole? I thought that you were making a joke?

Looking at the new pics, something looks wrong in the clutch department. Removed it and put up some pics of it and the sprocket drive area as well. The clutch doesn't look right. Is the sprocket mated correctly with the oil driver?

 

[HarleyT]

Is the drive sprocket .325 as well? A Stihl bar and chain won't work.

 

[MartDalb]

Is the drive sprocket .325 as well? A Stihl bar and chain won't work.

Ah you are right. The bolt fitting doesnt match. Dang, might have to purchase a brand new bar then.

And yes the sprocket is .325.

 

[HarleyT]

The clutch doesn't look right. I am not familiar with the model, but the crankshaft flush with the sprocket, I would think. So the sprocket drum may not be meshed with the oil pump driver correctly.

 

[MartDalb]

The clutch doesn't look right. I am not familiar with the model, but the crankshaft flush with the sprocket, I would think. So the sprocket drum may not be meshed with the oil pump driver correctly.
View attachment 1017785

The clutch spring is brand new, just replaced it.
All things clutch, wormgear should match out. (mine is the version with metal worm gear/oiling while idle etc)

See picture. Hope it makes sense.
I checked all those points, and they are like the IPL.

 

[huskihl]

Ah you are right. The bolt fitting doesnt match. Dang, might have to purchase a brand new bar then.

And yes the sprocket is .325.

He’s saying that your clutch isn’t threaded on far enough, which might be taking your sprocket and chain out of alignment. The drum should engage the oil worm gear and go in 1/8” further

 

[MartDalb]

He’s saying that your clutch isn’t threaded on far enough, which might be taking your sprocket and chain out of alignment. The drum should engage the oil worm gear and go in 1/8” further

ah. I totally missed that. Thank you both for clearing/pointing that out.
I will get on it and check!

 

[MartDalb]

Update - no luck on the clutch part.

See images, hope it is visable.
This model does not have the clutch drum reach the oil gear, since the worm is placed on the crankshaft itself.
But as pictures should show, it is as far as the clutch goes on.

 

[MartDalb]

So I am back to, the little rubber part was already bad? It cracked when I pulled out the adjuster screw/nut, or it is a chain/bar issue.

I will test the bar + chain on another saw, and steal the other and test.

But waiting for a replacement rubber part, these things always break don't they?

 

[MartDalb]

Being a brand new, as in, 10 minutes use time, chain, could this.... contribute to further seem like a loose chain problem? I wonder....

We have gone through every single thing here, and I have seen worn bars, this is not a worn out, damaged bar.

Any further feedback is welcome