Sthil bar smoking

[spamanon]

Hello,

I recently purchased a new Sthil ms291 for firewood cutting.  I cut a half a cord with it one week and it ran like a dream compared to my old Echo.  But this weekend I went back to the mountain and tried again, but something had changed.  Here are the symptoms:

• Very slow cutting.  Like 5 minutes to get through a 14" diameter log
• Overheating. The bar got so hot I couldn't touch it and it was smoking along the length.

Now the extra information.  When I first got to where I was going I tightened the chain just a half turn of the screw.  I was still able to pull the chain from the bar fairly easily, but it didn't sag.  I also filled it with bar oil and noticed it was consuming the bar oil as it went, so it isn't a dryness problem.  When I got home I found information on the internet that a pinched track or bent bar could do this, so I looked for both.  I didn't see anywhere the bar is pinched, and the sprocket on the bar end turns easily and freely.  Also, I am able to pull the chain along the bar and it seems smooth and easy to pull. When I laid the bar on a level and pressed one end down I was able to observe perhaps a 4-5mm gap on the other end.  Could that slight of a bend produce those symptoms?  Images attached.





 

 




 
 

 

[lxskllr]

Welcome! Is your chain sharp? Throwing chips or dust?

[spamanon]

Hello lxskllr,

I am not sure if the chain is sharp or what the chips looked like.  That's part of what I am wondering about: would a chain be dull after cutting 1/2 cord of pine?  That seems awful fast to me, but perhaps it's normal?

[lxskllr]

That's a little fast for overheating the bar dull, but definitely possible, especially if you ended up in the dirt at all, or the wood was dirty. A sharp chain should make nice chips. They'll feel crunchy and substantial if you grab a handful. If the saw's producing dust like you might see from a circular saw, it's really dull.

[thecfarm]

Sounds like a dull chain. Really have no exact idea how long a saw should go through a 14 inch,what I think you said a pine log,but 5 minutes is way to long.   I think I can do it in less than 10 seconds,easy. When my chain is sharp or flied correctly,it will draw itself into the log all by itself. Not a safe thing to do,but I can/could hold the rear handle and it will cut through the log without me pushing down or riding the saw back and forth.Don't try this at home. :D   I don't do it,just saying ,it could do that.Helps to almost cut through the log and than stop,do this whatever length you have to,until you can se daylight under the log. Cut through there and then roll the log over and finish cutting your cuts. Might seem slower,but that keeps your chain out of the dirt. I also put some limbs under the tree to hold it up out of the dirt too.

[spamanon]

Thanks, everyone!  So the slight amount of bend to the bar probably isn't much concern? 

[lxskllr]

I don't think so, Though I haven't checked mine to compare. Sounds like a dull chain to me.

I was looking for a picture of sharp chain chips to show you, and ran across this page...

Chainsaw chain maintenance. Detailed guide

The picture isn't great, but you should be able to make out the difference, and I suspect your pieces are even smaller than the "dull" side of the picture. In any case, the page gives a decent overview of sharpening a saw chain. You may want to look into getting the Stihl 2in1 sharpening guide, or the Pferd guide(they make them for Stihl). I haven't used them, but the people that have really like them, and it'll help you easily get a good edge.

[Old Greenhorn]

If the oiler is working and the chain gets oil, I am thinking you chain can't cut. Can you post a pic of a handful of you chips from the saw. That will answer that question.

[DelawhereJoe]

How many times have you filled the chain? There is also the chance you nicked a tiny rock that was stuck in the bark

[A.thorp08]

From my experience in the woods cutting for a friend it sounds like a dull chain we run the yellow sthil chains and depending on the angle you sharpen and how much you take off the rakers will make a big difference. Try a new chain before going too crazy into thinking there is a bigger problem. I have a brand new chain and bar for my 460 that keeps throwing the chain it only happens with this one new bar I have 4 others I run with no issues my old 24" the 24" I have drilled out for my mill guide a 20" the same setup and a 20" that I like to top with. This new 24" bar has me confused about what the problem is. 

 

[longtime lurker]

Bars pinched. see that dark mark on the side under the s in boss? right there, and I can see it in the groove pictue as well about half way between your wrist and toe in the middle pic. Chains also blunt, rails are starting to burr because of it.

Or maybe its me with no glasses on. :D

[mredden]

Roll the appropriate sized coin through the groove. If it sticks in a spot, you're bar is probably pinched at that spot. In truth, a quarter is .069. a penny is .0598 and a dime is .053. So, they are all slightly larger than the corresponding drive links. Of course, the bar groves should be slightly larger for the drivers to move through. Anyway, I have found the coin test to work on my .050 and .063 bars. Don't know about the penny/.058

[Al_Smith]

5 minutes on a 14" round ,my goodness . I could be a smart aleck and ask if the chain is on backwards but I won't .

[longtime lurker]

5 minutes on a 14" round ,my goodness . I could be a smart aleck and ask if the chain is on backwards but I won't .

Voice of experience talking?
Yeah, I've done that before, but on a slabber not a regular saw. :D

[spamanon]

Thanks everyone. I bought one of those Stihl sharpeners and ran a couple of scrapes on each other teeth and it seemed to have worked. Went through 12 inch log in under a minute now. Here is the dust that came out the back. Does this look better?


 

[realzed]

Hard or soft wood chips? Looks like certainly better than a dull chain might throw - but not as good as a real good sharp chain would produce especially if the wood is soft.  Could also be that the rakers are sitting up a bit too high but I think you said it was a fairly new chain and hadn't been sharpened previously, so that should probably not be relevant at this point. 

[lxskllr]

Kinda looks like high rakers to me too. Did you get the 2in1, or the regular file guide?

[spamanon]

Yes it's soft wood.  The chain has only cut up 1/2 a cord before sharpening.   I got the 2 in 1.  I can give it a few more swipes with the sharpener. 

[spamanon]

Well I ran the sharpener over the bar a few more times and took it out again today.   I think it cut better than when it was new!  That worked so well I couldn't believe I could get OT that sharp my first time sharpening a saw.

Thanks to everyone for helping me out on this.   Now I know what a dull chain does!   Love my Sthil! 

[btulloh]

Looks like you've got it whipped. Sounds like you'll be sharpening often from now on. Throwing chips is addictive.  ;D

[Al_Smith]

5 minutes on a 14" round ,my goodness . I could be a smart aleck and ask if the chain is on backwards but I won't .

Voice of experience talking?
Yeah, I've done that before, but on a slabber not a regular saw. :D

Well just about everybody has done at least three things if they are honest, chain on backwards ,oil in the gas tank ,cut the ground --guilty as charged. ---things happen 

[lxskllr]

Well just about everybody has done at least three things if they are honest, chain on backwards ,oil in the gas tank ,cut the ground --guilty as charged. ---things happen  

Haven't done the first two ever, but I've made up the slack on the third. Sometimes I like to mix it up, and cut some rocks after cutting dirt for awhile  :^/

[Al_Smith]

My departed dear old pappy oiled his gas on his old McCulloch twice in one week .He was 82 at the time and passed at 86 .The old trick then was fire it up using WD-40 that at that time used propane as a propellant .It really smoked like it was fogging for mosquitoes for a short while .I own that PM 610 now and it's no worse for the wear .

[thecfarm]

Put the saw into the "dirt" on this land and you are into a rock. One reason I can sharpen a chain very well. Yes,might take me 3-4 sharpening to get the chain back cutting good,but I can do it. But I also like my stumps very low. Blame that on my Father.

[ManjiSann]

5 minutes on a 14" round ,my goodness . I could be a smart aleck and ask if the chain is on backwards but I won't .

Voice of experience talking?
Yeah, I've done that before, but on a slabber not a regular saw. :D

Well just about everybody has done at least three things if they are honest, chain on backwards ,oil in the gas tank ,cut the ground --guilty as charged. ---things happen  

Glad to know I'm not the only one who has put B/C oil in the gas tank  ;D ;D  I've done the second two, so far been able to avoid the first.  
I've learned how to sharpen chains pretty well due to running them into the dirt, mostly from needing to cut the stumps within an inch or so to the ground. 
Brandon