Chain is tight, slips off then inside teeth get damaged.

[mikegondek]

Husqvarna rancher 450. I put the chain on tight to the point where it doesn't move then I loosen it a little bit so that it will move by gloved hand.

I might use a chainsaw for about 3 minutes the chain then slips off. It does not look very damaged, but the inside teeth get damaged as it's super tight in the bar channel. I use the Dremel to saw down some of the burrs and able to get it back on. That takes a lot of time so I'm not gonna be doing that anymore.

The bar isn't damaged, but using today I noticed that this aluminum colored guard, had the whole top side detached and curled over.

The picture with the red circle shows where I filed off that chain guard. The second picture shows what it looks like properly on my other chainsaw, which is the exact same model.




My question is why do you think my chain is falling off? Is that chain guard really important should I buy a new one and replace it? I don't wanna waste any more chains, playing around with this as I've lost three already until I found that guard was damaged.

Also, does the rancher 450, have a pressure release valve, that you are supposed to engage prior to starting. Maybe it's already incorporated in the choke? It's usually a blue or a black button on chainsaws.

 

[mikegondek]

Found a diagtram and this is th4 part I plan to replace.
544094001 Chain Guide Plate

From the pictures I posted do you believe my issue is that the chain guard plate got damaged? Could it be something else. Is it worth replacing over that top part gaurd getting chewed up and missing now? I hate to destroy any more chains chasing this.

 

[Bob Hedgecutter]

Yeah looks like the chain has been contacting the plate and bent it all out of shape- but the chain looks absolutely rocked out or ground struck as well.
Now way that chain is cutting wood the way a sharp chain will- and I do not just mean the side that has been contacting the plate.

 

[mikegondek]

Not sure what caused the guard plate to get damaged, maybe the chain got loose and knicked it 3 chains ago. Do you think if I should replace the guard plate? Will it work now that I cut out removed the gnarled part top portion, or should I replace it. Seems like a poor design as any contact with the chain would destroy it, being the slightly thicker only than an aluminum beer can.

 

[Bob Hedgecutter]

I would replace it myself and try to figure out why it is happening.
Chains you have are all the correct gauge and pitch?
Suit the bar?
Any damage to the drive links of the chain?

Photos of the bar rails at the tail of the bar, drive sprocket on the clutch drum and drive links of the chains would be handy.