Chain keeps loosing up on my stihl ms250c.

[randellog]

When I am cutting with my stihl saw that has the toolless chain adjuster, I don’t cut but a few minutes and the chain Loosens up. I retighten it and it will loosen up constantly. I am wondering if there is a way to change the adjuster to the type that has the two nuts and screwdriver adjuster.

 

[Brushwacker]

It might be more trouble then it's worth; pretty sure it's been discussed here before.
I expect your sprocket might be worn past its practical limitations, you are cutting dirty wood or tryiing to cut with a dulled chain. 1 or maybe a combination of these things.

 

[Lightning Performance]

They don't move that I've ever seen

 

[HumBurner]

When I am cutting with my stihl saw that has the toolless chain adjuster, I don’t cut but a few minutes and the chain Loosens up. I retighten it and it will loosen up constantly. I am wondering if there is a way to change the adjuster to the type that has the two nuts and screwdriver adjuster.

Does it do this on a new chain?

Like brushwacker said, it could be the sprocket. Also double check the sprocket-tip of the bar for loose bearings or splayed rails.

Lastly, as chains go through their lives, it may be necessary to have a link removed, as the chain will be longer than the chain adjuster can tighten properly.

 

[blades]

Quality of chain has a lot to do with this. I have been fighting some this also. Lack of oil will cause excess heat whch in turn will cause excess streching of chain. Seems like a lot of the .050 size chain out there is not made as well as it once was. I have had to shift to .058 and .063 in 3/8 pitch to get around the problems. also quality of the bar has an effect also- I have had some less than steallar results from some brand name units over the last couple seasons. sure is PIA not to mention $$$ when a bar dosen't last a season. Primarily 20" and 24" bars as those lengths are what I am useing 80% of the time.

 

[farmer steve]

Make sure you didn't loose the small screw that holds the gear on the bar or make sure it's tight. My dad had the same problem on his ms170. He didn't realize he had lost the screw.

 

[randellog]

It might be more trouble then it's worth; pretty sure it's been discussed here before.
I expect your sprocket might be worn past its practical limitations, you are cutting dirty wood or tryiing to cut with a dulled chain. 1 or maybe a combination of these things.

This subject may have been discussed before but I just joined the group. I somehow found this group and when I tried to see the answer to another person explain that they had found a fix for this problem, I tried to open it up to find out what he did. I had to join the group to see that information. I could not find that thread anymore so I asked the question again hoping to get the person who responded to answer me. I have been using a chainsaw for cutting firewood for nearly 40 years, and I know a lot of the responses that have been brought up. Please don’t think that I am being sarcastic about your answers, I assure you that I appreciate any information I can get. This chainsaw has done this every since I purchased it. I was just trying to see if there was a way to change it, because other than this problem it is a good saw. I have owned this saw about 5 years now and would love to fix it. Thanks.

 

[randellog]

Make you didn't loose the small screw that holds the gear on the bar or make sure it's tight. My dad had the same problem on his ms170. He didn't realize he had lost the screw.

I will check this. Thanks.

 

[randellog]

Does it do this on a new chain?

Like brushwacker said, it could be the sprocket. Also double check the sprocket-tip of the bar for loose bearings or splayed rails.

Lastly, as chains go through their lives, it may be necessary to have a link removed, as the chain will be longer than the chain adjuster can tighten properly.

It has been doing this every since it was new almost, I thought that this system would be great but it has been a nightmare. it not a chain issue it’s a design issue on the saw, and I was just trying to change it if I can. Thanks.

 

[randellog]

It might be more trouble then it's worth; pretty sure it's been discussed here before.
I expect your sprocket might be worn past its practical limitations, you are cutting dirty wood or tryiing to cut with a dulled chain. 1 or maybe a combination of these things.

The post I saw and can’t get back to said that there were several parts that could be changed that would allow you to convert it. He even had a list of parts that was needed with part numbers. I think that he said that it would cost around $50 to convert it. l would spend that much if it would solve my problem. I would never buy that design again,ever.

 

[ChuckMI]

The post I saw and can’t get back to said that there were several parts that could be changed that would allow you to convert it. He even had a list of parts that was needed with part numbers. I think that he said that it would cost around $50 to convert it. l would spend that much if it would solve my problem. I would never buy that design again,ever.

bit.ly/3VXSwNW plus bit.ly/3Xm0FNt The Amazon reviews for the screw part are very poor but the listing gives the OEM part so you could get that from the Stihl dealer or you could take the pictures to the Stihl dealer and get it all from him. I bought a kit that included all the parts and it has worked fine but is no longer available.​

 

[user 74409]

What is needed is one bar stud, tensioner assembly with mounting screw, clutch/sprocket cover and 2 bar nuts. eBay is good source for new or used.

I pasted an old post below that includes part numbers than you referred to in one of your messages.

 

[abbott295]

Maybe, just maybe, the chain and sprocket are not the same? 3/8 vs 3/8 lopro for example?

 

[coffeebrk]

I run both the ms251 and ms251c and my 251c keeps chain tension just like my 251. I do keep the 251c chain cover very clean of oil and sawdust. The cover easily disassembles for a complete cleaning of all the parts.
Have you ever measured the bar tip to cover before you cut? Then measure again when the chain loosen up. That will tell you if the bar is slipping

 

[sand sock]

When I am cutting with my stihl saw that has the toolless chain adjuster, I don’t cut but a few minutes and the chain Loosens up. I retighten it and it will loosen up constantly. I am wondering if there is a way to change the adjuster to the type that has the two nuts and screwdriver adjuster.

i rubbed some bees wax on the threads of my 562. it was loosening right up. fixed it pretty quick.

 

[Syflan]

Dang! I've been griping about this "easy" tensioning system ever since I bought the saw. For some reason I figured it would be hard to convert it to the "hard" system. Amazon has Chinesium kits for doing the conversion for under $20, price seems to depend on whether it's a side or front tensioner.

Now if only I can convert those Stihl 1/4-turn fluid caps to regular screw-on...

 

[randellog]

What is needed is one bar stud, tensioner assembly with mounting screw, clutch/sprocket cover and 2 bar nuts. eBay is good source for new or used.

I pasted an old post below that includes part numbers than you referred to in one of your messages.
View attachment 1047575
View attachment 1047576

Thank you so much for this information. I will try and find the parts now to change it. I thought the tool less system would be great but it has been a pain.

 

[randellog]

Dang! I've been griping about this "easy" tensioning system ever since I bought the saw. For some reason I figured it would be hard to convert it to the "hard" system. Amazon has Chinesium kits for doing the conversion for under $20, price seems to depend on whether it's a side or front tensioner.

Now if only I can convert those Stihl 1/4-turn fluid caps to regular screw-on...

I have felt the same way, every since I bought mine also. I never knew that you could change it. I found this page by accident and low and behold the first thread was I saw was the one about this problem.

 

[psc1947]

Scribe a line on your Bar against the plastic cover with the chain properly adjusted. Then when the chain gets loose see if your line moved in, if it did the adjusters not holding. Looking at my MS211C I don't see a quick fix like I have on a Husky by simoly adding two nuts. Stihi tension knob is too flimsy to add a set screw.
maybe taking a pointed drimmel and rough both the friction mating surfaces If slippage is the problem. MS211C was a big disappointment because of chain size. Swapped out sprocket, bar and chain and actually like it now. At 75 yo I wanted a lighter saw.

 

[randellog]

Scribe a line on your Bar against the plastic cover with the chain properly adjusted. Then when the chain gets loose see if your line moved in, if it did the adjusters not holding. Looking at my MS211C I don't see a quick fix like I have on a Husky by simoly adding two nuts. Stihi tension knob is too flimsy to add a set screw.
maybe taking a pointed drimmel and rough both the friction mating surfaces If slippage is the problem. MS211C was a big disappointment because of chain size. Swapped out sprocket, bar and chain and actually like it now. At 75 yo I wanted a lighter saw.

I think that I found a link to some parts to change it over to a manual adjuster, which is what I wanted to do. So I am going to try to find those parts. I fell out of love with the easy adjuster pretty quick.