Hot Stihl 251

[Micah16858]

Hi, new guy here. Just bought my first saw, a used MS251. The dealer said the previous owner ran it with the chain brake on, returned it, and bought a new one. So, he said he replaced a couple of things, but it's like brand new. And I paid two-hunnerd for it. Good deal?
One interesting thing is that it has two bar studs, instead of the one that the stock 251 has. My question here is, it gets pretty warm when I'm running it, including the B&C, the top plastic cover over the cylinder, and the clutch (bell?). It's not plastic-melting hot, but I couldn't touch it for more than a second or two. The bar is clean, the oil holes in it are clear. It's not throwing oil off the chain, but the chain looks very lightly coated with oil. Is this okay? I believe it has a non-adjustable oiler.
I tensioned the chain so that, at the bottom of the bar, the drive lugs sit in the bar rails, but theres a small gap between the cutters and the bar. Is this correct?

 

[Full Chisel]

"Like brand new", huh...

 

[Chainsaw Jim]

Maybe you can take it back and have the guy who sold it show you the proper chain tension. and if the oiler is malfunctioning then maybe he'll be willing to help you out.
You don't want the chain hanging, but you don't want it so tight that it creates resistance. you can feel it spin easier as you loosen it, so tighten it until you start feeling the tension work against the chain and back off just a tad bit. hold the bar up as you tighten the bar nut. smaller saws like to clinch the chain a bit tighter as you tighten the bar nuts down, so you may have to re-loosen and readjust to compensate.

 

[Hinerman]

 

[Micah16858]

Alright, I think I know what the problem was. There's a little tab cutout on the clutch cover that's supposed to fit on a piece of metal in the clutch. (Worm Gear?) Well, it wasn't on. So I assume the only oil I was getting was the friction of the clutch cover spinning against it, because the saw was using some oil, but not near the amount that came out when it's hooked up right. I hope I didn't burn anything up, only used it for ~20 total minutes. Anybody know why, or how it's got two bar studs?

 

[Chainsaw Jim]

Anybody know why, or how it's got two bar studs?

The 251c is the model with the tooless chain tensioner. The models without a "c" have two bar studs on the 250. the 251 should have one.

 

[Franny K]

I have the base model 251 and it has only 1 bar stud. The 250 has two bar studs I would like to see a picture of what you have. I guess they could have changed things but think I would have noticed that at a Stihl dealership by now. Apparently they have added wood boss to the name but show one bar stud and an adjuster hole. http://www.stihlusa.com/products/chain-saws/homeowner-saws/ms251/

Are you saying a Stihl dealership sold you a saw that the clutch drum was not lined up with the oiler drive tang? There is a mini spline kit to run rim drive (stihl ones) in picco or 0.325. The picco with 7 tooth is generally what I use.

 

[Chainsaw Jim]

can you show a pic of the saw?

 

[Jed1124]

There was another thread on here a couple of months back where a 251 burnt up the clutch. The guy got accused by the dealer of running the saw with the break on. Most of the guys on here figured the same.
Maybe these saws are prone to this problem?

 

[Franny K]

There was another thread on here a couple of months back where a 251 burnt up the clutch. The guy got accused by the dealer of running the saw with the break on. Most of the guys on here figured the same.
Maybe these saws are prone to this problem?

I do not think that way. The brake actuates easily and positively with a definite click. If I am not mistaken the manual says to start the saw with the brake on and on the fast idle position. Perhaps folks are not blipping the throttle to get to normal idle. There is another thing, my clutch drum is not centered in the spot for it. It is closer to the bar. I can't say it was that way from new but it has been that way for at least 90% of it's life since I noticed. It might be possible others are worse than mine. It isn't a bad habit to pull that drum out every now and then, seems there can be a bit of build up just inside of the shoes that can make it hard to pull out.

 

[Micah16858]

Here's some pics of it. I assume the bar paint is all buggered up because it's gotten hot and flaked off? Or is that just a Stihl bar thing. It was like that when I got it. Also, how do you measure the bar length? From the front of the saw to the tip of the bar, or the length of the entire bar? Thanks

 

[big t double]

that doesn't look like the clutch cover that comes stock on 251's...more like an 1123 series cover... ive never seen a 251 with two studs though. interesting. can you get a pic without the cover, bar or chain on? I wonder if someone rigged that up like that. looks like the studs are different colors...not that that means anything.

 

[Franny K]

Maybe the rear post can be swapped out with a stud. As much as I dislike the one bar nut there is a limit to how hard one can push things before some semi-solid contact is made and vibration changes.

It is a called bar length. If there is enough origional surface on the bar it will say some information. If not count the drive links and match that number with what they call. That much paint (missing) isn't nearly new in my estimation. Getting the bar pinched or squeezed some would likely make the paint go away sooner, even more so in abrasive conditions.

 

[Micah16858]

Maybe the rear post can be swapped out with a stud.

That's what it looks like.

 

[Lee1982]

That's what it looks like.View attachment 438887

That bar stud closest to the clutch drum isnt stock. But i may do that to my 251 since im not a big fan of the single stud setup either. My 251 got hot also when i was using it with very thick gloves (in January). The back side of my left hand engaged the brake and i didnt realize it(very loud with other saws/splitters running) and let it idle while i took about a five-ten minute break . Darn thing melted the plastic cover, destroyed the needle bearing and cooked the clutch drum. When my local dealer tinkered around for about 4 months and never fixed it, i took matters into my own hands. I have everything back to new condition except the oiler/worm gear. it seems to be missing after the dealer did their thing. any help would be greatly appreciated...

 

[drf255]

Your missing the chain catcher as well.

That bar is OLD. The paint simple wears off from heat and abrasion. It may be just fine tough.

 

[Lee1982]

Your missing the chain catcher as well.

That bar is OLD. The paint simple wears off from heat and abrasion. It may be just fine tough.

The chain catcher on the 251 i believe is built into the clutch cover held on by the nuts. It lines up with that diamond shaped hole but as mentioned earlier, this isnt the OEM clutch cover

 

[a. palmer jr.]

The saw has been changed over to the two stud setup from the one stud or the tool less adjuster. I changed one over this year, not very hard to do. Yours has an older cover on it, the color is slightly different and could have come from an MS250 or any of the smaller older Stihl saws of last year or earlier. It's actually an improvement. I wouldn't start one of these with the chain brake on because of all the plastic around the clutch but don't have a bunch of people around while you're starting it.

 

[Micah16858]

Alright, I ran it again today for a little bit, and the B&C still get pretty hot, just after a few cuts. It's definitely using oil, you can see it coming out the bottom of the saw, but the chain is pretty much dry. I also noticed the chain got tight after the first few minutes, I retentioned it and it seemed fine. It just seems to me that the opposite would happen if it heated up, that it would get loose. I guess the bar expanded more than the chain did, and that's why it got tight. I'm gonna take it back to the dealer tomorrow, before it gets too hot and hurts something. Possibly a different bar? It looks like the holes line up, but then again, I'm not exactly an expert.

 

[porsche965]

Take it back.

These plastic saws don't take abuse well via heat. The chain case cover has been hot. Notice the discoloration? And for a bar to look like that, unless it was a real novice running it, has way more than a few tanks on it. If this was a Mag Case saw you probably would be fine replacing things and cutting wood, but plastic case and heat don't mix for long. Take it back.