stihl ms251

[SawTroll]

.... Some things remain the same though, like you and me. We pester each other all in fun but you know I would back you up in a heartbeat if you needed me, cheers!!!!!!!!

Yes, I know ol' friend - has happened before.

 

[jdind]

Been looking at a MS 251 for a while now. Finally bit the bullet and got mine yesterday. I must say I'm rather unimpressed so far, mostly by the crappy single bar nut design. Due to the bar not getting oil at first, I took the clutch cover on and off a few times. At one stage, as I was unscrewing the single bar nut to release the cover, the whole bolt started coming out of the plastic casing! I managed to get it back in, but still, it doesn't inspire much confidence. Nor the fact that Stihl has a spare oversized bolt in their catalogue (must happen a lot).
I since checked the owners manual and it says that the bar nut should be 'finger tight'. That sounds rather light on, especially when there's only one nut and a crappy plastic chain guard (the metal one doesn't come as standard, apparently???)
The overall design is really pretty crap: there's a second bolt that the bar slides into, but for some reason there's no way to use that second bar bolt to tighten the bar, WTF?

 

[radioFlash]

The "finger tight" recommendation is before you tension the bar chain. Once the chain is tensioned properly, the manual suggests "while holding the bar nose up, tighten the nut firmly"--pretty vague too. I found a Craftsman chainsaw manual for a 42cc saw that suggests 10-15 ft-lbs of torque.

I think I saw it mentioned somewhere that it's possible to fit a different sprocket cover and convert it to a two bolt mount.

I forgot to tighten the nut a couple of times and threw the chain, which chewed up the plastic dust cover, which fortunately was pretty cheap. My saw only had the integral plastic chain catcher on the sprocket cover (now chewed up on mine), but the part number for the metal catcher is 0000 656 7700 and it's only a few dollars.

 

[Rockjock]

The 251 has been a good seller for us, and seeing that several were sold to a crew that take down ash trees they got some serious hours on them with no issues thus far. I also got to use one in November in Deutschland to help a friend drop some trees and cut up some firewood. Again I found no issues with it. I am used to my 025 and thought it was a nice upgrade. Better AV and air filter. and yes the flippy caps.

 

[jdind]

The "finger tight" recommendation is before you tension the bar chain. Once the chain is tensioned properly, the manual suggests "while holding the bar nose up, tighten the nut firmly"--pretty vague too. I found a Craftsman chainsaw manual for a 42cc saw that suggests 10-15 ft-lbs of torque.

Oh yes, I didn't see that when I looked through the manual. Certainly better than finger tight, but still pretty vague as you said.

I think I saw it mentioned somewhere that it's possible to fit a different sprocket cover and convert it to a two bolt mount.

I rang the shop and asked them, but they couldn't figure out a two-bolt cover that would fit the 251. :-( If anyone knows of one I'd love to hear it.

 

[Franny K]

Oh yes, I didn't see that when I looked through the manual. Certainly better than finger tight, but still pretty vague as you said.



I rang the shop and asked them, but they couldn't figure out a two-bolt cover that would fit the 251. :-( If anyone knows of one I'd love to hear it.

Look at this thread
http://www.arboristsite.com/community/threads/hot-stihl-251.283651/
post 18 is the closest to an answer.

I thought about converting mine but have not. The anti vibe is pretty flexible, there is not a lot of composite material for the bar to press against where the new stud would go. The pin/peg does conveniently have a torx recess for taking it out.

I was looking on line at the manual and parts sheet for the Husqvarna 445 which I suspect is the comparable model. The Husky has 33mm stroke instead of 30. Ms250 had has 32mm. I only see a 7 tooth spur in 0.325 for the Husky where there are many choices for the Stihl being discussed here.

 

[Chris-PA]

And I thought 2 bar studs screwed into plastic threads was cheap and an inappropriate design given the materials.

 

[Franny K]

And I thought 2 bar studs screwed into plastic threads was cheap and an inappropriate design given the materials.

I believe it is composite instead of plastic.
It may be a better choice than using a T type b0lt and doing something different.
It would be interesting to do some destructive testing with the scrench/multi tool they provide with a saw purchase and see how hard it is to pull the threads out. What is the chances the threads on the nut pull out first.

 

[Chris-PA]

I believe it is composite instead of plastic.
It may be a better choice than using a T type b0lt and doing something different.
It would be interesting to do some destructive testing with the scrench/multi tool they provide with a saw purchase and see how hard it is to pull the threads out. What is the chances the threads on the nut pull out first.

It's a plastic with filler - they're all using the same kinds of materials. The shear strength of those tiny threads is never going to compare to pulling a steel bolt through the case. You still need to keep the bolt from rotating, but a square head will do that fine.

It would be an interesting test but I'd bet on this:

 

[Franny K]

This is another way of doing it.
I would most certainly like to have two bar studs and a metal plate that contacts the bar and saw chasis. On this model even a clutch cover that spread the load out a bit more and didn't mar the paint on the bar would be an improvement.

 

[rynosawr]

Ok, my first hand opinion of the MS251....


I bought one that had the muffler fall off and it roasted and melted the inside of the case/body very badly, warping several parts of the chain brake mechanism enough that it still worked, but barely.

This was bought from the same owner/abuser as the hottest MS391 thread so I wasn't surprised.

I thought this saw had ruined crank bearings but it didn't, it had so much crud/varnish on the piston that it wouldn't hardly turn over when I got it.

Did a complete dissasembly and full cleaning and found a ton of carbon and varnish on the piston skirt and stuck rings.... This saw was less than a year old and had been used by some abusive tree service guys.

Put it all back together and started in two pulls cold and one warm. It has a funny noise to the clutch/kind of a whirring sound others have mentioned.
Oiler oils ok, but minimal.

Power seems ok, but I prefer an 024super or 026 old school saw feel.

I sold it for $240, but there wasn't much interest in it locally, which was odd to me. The shop I get parts from didn't recommend one very highly either.


My $.02.....


Buy a good used or rebuilt 024 or 026 on here (AS) before buying one of these Mattel saws.... I know everyone wants a new saw, but you can't beat the quality of a good used magnesium pro saw that has been well maintained.

The Dolmar 421 does look very good as a new saw also.

 

[melloyello]

I have been using my 251 for 2 years. Normally it gets 2-3 tanks ran through it then the cover, chain and bar gets taken off and everything is blown out. The top cover comes off and is blown out. I also blow out around the muffler and blow out what fins I can get to. I do this with all my saws. I think taking care of your saws has a lot to do with how long they last.
Never had a problem with the one nut on the cover. I would like to see more oil on the bar though. I have seen that if I use Poulan Pro oil in it instead of Stihl oil it oils more. I have actually thought about running motor oil in it to get it to oil better. Aside from the oiler I don't have any other problems with the saw. It's light and has plenty of power for what I do with it. If I need more power I grab the 391. If I need less I grab the 170.
I have a few saws and haven't had any major failures. I have repaired many saws that have had major problems. Most of these problems could have been stopped by keeping the saw clean, keeping the chain tensioned properly, keeping the chain sharp, servicing regularly and using the saw as it was intended.

 

[rynosawr]

I have been using my 251 for 2 years. Normally it gets 2-3 tanks ran through it then the cover, chain and bar gets taken off and everything is blown out. The top cover comes off and is blown out. I also blow out around the muffler and blow out what fins I can get to. I do this with all my saws. I think taking care of your saws has a lot to do with how long they last.
Never had a problem with the one nut on the cover. I would like to see more oil on the bar though. I have seen that if I use Poulan Pro oil in it instead of Stihl oil it oils more. I have actually thought about running motor oil in it to get it to oil better. Aside from the oiler I don't have any other problems with the saw. It's light and has plenty of power for what I do with it. If I need more power I grab the 391. If I need less I grab the 170.
I have a few saws and haven't had any major failures. I have repaired many saws that have had major problems. Most of these problems could have been stopped by keeping the saw clean, keeping the chain tensioned properly, keeping the chain sharp, servicing regularly and using the saw as it was intended.

You make some excellent points. I think you are 100% correct. If these saws are well maintained and cleaned regularly, they will last a long time.

It is really only in a harsh use and abuse environment that they are prone to fail.

I wish saw manufacturers would quit making saws with crevices and cubby holes for crap to get stuck in.....

It would make for much easier cleaning and maintenance, of course, they wouldn't sell as many saws because of that either....

I wonder sometimes what the marketing, engineering, and accounting teams say to each other every time a new generation of chainsaw is devised.

 

[Rockjock]

I received a PM from a bloke reminding me of a video where this chap drops a fairly substantial tree and bucks it up with a MS 251 and a 14" B&C take your time and get it done..