Chain Getting Stuck on Bar Sprocket

[Mitragorz]

Hey guys, first post here.

I’ve got a Stihl MS290 that I’ve been using to take down some trees in the yard. Was running great for a few days. Then all of a sudden, the chain just started getting stuck. I’d be in the middle of a cut and it would just stop.
After a handful of times of taking the cover off, bar off, chain off, I noticed that the bar sprocket was completely worn. The teeth were flush with the bar, no protrusion at all.

Ok, so new bar and new chains ordered. Got the new bar today, same part number as the original (I’m guessing) bar.

I get in a few cuts and the same thing starts happening. Chain is stuck. Tension seems fine, adjusted the way I’ve been running the saw for years.
Take the bar/chain off, spin the bar sprocket... Moves freely. Put everything back together, give the chain a spin. Still good.

Put it to wood, 15 seconds in, chain stops again. Take it all off again, but leave the chain on the bar.
Clutch spins freely. Chain will not move on the bar.

I noticed that the inside teeth of the chain were actually jammed between the bar and bar sprocket.
That must’ve been what happened to the old bar. Obviously is something I’m doing/not doing. Chain tension seems fine. Maybe the oiler needs to be adjusted (if it can be on this saw)?

What do you guys think? Pic is attached. This isn’t the worst jam, so it’s tough to see... But you can see that the nub is “next to” the chain tooth, and not in between them. I put the saw down and used my little 14” Harbor Freight electric saw that’s usually reserved for branch duty. Got the rest of today’s work done, slowly but surely

 

[cuinrearview]

Looks like mis-matched pitches. Also, if your bar was worn did you look at your drive sprocket?

 

[jjcard41]

Hmm...chain type matches up with bar requirements?

 

[cuinrearview]

If your drive sprocket is messed it could ruin the drivers.

 

[PV Hiker]

Picture of the sprocket? And side view with bar and chain on, no cover?

 

[Mitragorz]

Wow, didn't know the pic was going to post that big!

Ok, here's more info for you guys. Bar and chain are right for the machine: Bar is Stihl 3003 008 6821, same as original. Chain is Oregon E72.

Picture of the sprocket? And side view with bar and chain on, no cover?

Pics of the sprocket. I already had the bar/chain off... The kids are screaming and I'm pretty sure if escaped to the shed again to take a pic of the setup minus cover, the wife will probably lock me out.

 

[cuinrearview]

You need a new sprocket. It's damaging the part on the chain that it engages.

 

[HarleyT]

You have a full 3/8 chain on a .325 sprocket....

 

[Mitragorz]

You have a full 3/8 chain on a .325 sprocket....

So what chain should I be using? The D/E72 chains I've been running both list the MS290 on the back.

Or is it the sprocket that is wrong?

 

[HarleyT]

The bar number you show is a .325 as well.

 

[HarleyT]

So you need the Oregon 22lp81.

 

[gumneck]

If you run the saw and point the tip at something to catch the oil (cardboard or end cut of a log) and rev the saw that should be slinging off the tip so you can see it. You should see oil slinging off the bar.

 

[HarleyT]

Here.

 

[Mitragorz]

The bar number you show is a .325 as well.

Yup, just pulled the box out and saw that.

So you need the Oregon 22lp81.

I'll look that one up. Why would Oregon list the machine as compatible if the pitch is wrong? Is that common? I never paid any attention to the numbers, I'd just go to Home Depot and pick the 20" chain off the shelf that had the machine listed on the back.

 

[cuinrearview]

It will run either pitch, the parts have to match though.

 

[PV Hiker]

Your sprocket as HarleyT mentioned is .325. Your bar is .325, 20 inch .063 gap. Look at the stamp on the side of the bar will tell you what chain size and drive links you need. You should then look for a chain with those requirements. Cutter tooth choice is yours.

 

[PV Hiker]

You guys are fast! My comment seems old since I missed a lot while I was typing it.

 

[Mitragorz]

So you need the Oregon 22lp81.

I wasn't able to pull that number up on the Oregon website, but putting the machine, .325" pitch and .063" gauge spit out some results. I assume any of those would work just as well?

Also, are any of the Amazon brands of sprockets/clutches worth it? Harbot, ATVATP, Aisen, Stens, etc. or are they all cheapo knockoffs?

I'll call the local shop tomorrow morning to see what they have... If they're open with this whole virus thing...

 

[tfp]

I like this type of oregon chain for general purpose use

https://www.oregonproducts.com/en/powercut™-saw-chain,-20"/p/22lpx081g
Make sure you have the right size files as you might have ended up with files that match your incorrect chain (3/16 for .325).

Since you're replacing the sprocket, I change mine to a rim sprocket instead of a spur sprocket. If the cost is similar you could do that as well.

Please make sure everything matches!

 

[peak-industry]

If you want to replace sprockent, let shop knowing your saw model, to match sprocket model. Rim is better than Spur, costs a little more.