Stihl MS211/C problem with power in the cut

[spudulike]

Yup, it was a option 1,2 or 3 affair but from this it sounds like the saws clutch or sprocket has failed. I have seen the sprocket come away from the drum before and do this, the sprocket could be that worn, the chain is spinning round it, the clutch shoes or drum may be worn/deformed where they contact each other or the clutch may be faulty to the point the shoes aren't making correct contact with the drum.

At least we now know the saw appears to be making power and it is still revving even though the chain isn't spinning.

A video may be useful to support the description but at least we are on the way now!

 

[John Rainford]

Oops, I misunderstood the 1,2,3, question. After reading your replies I took a close look at the clutch and sprocket as well as looking at a couple of videos of clutch and drum issues. The sprocket has two grooves on each arm, which have been cut in to it to a depth varying between 0.5mm and 1mm so I guess your theory of the chain slipping over the sprocket without engaging could well be correct spud. The springs on the clutch look good, they haven't eaten in to the metal as I have seen can sometimes happen. Not sure how to check the brake shoes, will look that one up. I will post some photo's of the clutch and sprocket later today. You never know you might have solved the issue for me.

[NFG]

3 hours ago, John Rainford said:

Oops, I misunderstood the 1,2,3, question. After reading your replies I took a close look at the clutch and sprocket as well as looking at a couple of videos of clutch and drum issues. The sprocket has two grooves on each arm, which have been cut in to it to a depth varying between 0.5mm and 1mm so I guess your theory of the chain slipping over the sprocket without engaging could well be correct spud. The springs on the clutch look good, they haven't eaten in to the metal as I have seen can sometimes happen. Not sure how to check the brake shoes, will look that one up. I will post some photo's of the clutch and sprocket later today. You never know you might have solved the issue for me.

I would have thought a 1mm groove would not be sufficient to lose the drive from the sprocket and it would make a fairly horrible noise if it did. Can you post a pic?

I think, with the engine off, if you put the chain brake on then try and rotate the chain manually it would demonstrate if the spur drive is slipping or driving ok.

Edited January 18, 2020 by NFG

[ChrisNewport]

Is the chain on the right way round? I've lent a saw to my brother and it's come back on the wrong way after he took it apart to clean it before returning it.

[bmp01]

3 hours ago, John Rainford said:

The sprocket has two grooves on each arm, which have been cut in to it to a depth varying between 0.5mm and 1mm 

Those 2 grooves are in the OD of each tooth. The chain is driven on the face of the tooth, you will see a singIe wear mark on each tooth face - or with extreme wear a slot cut through each tooth (cuts the tooth more or less in half)....

One in the attached picture is worn but would still drive the chain. 

[Stubby]

5 hours ago, ChrisNewport said:

Is the chain on the right way round? I've lent a saw to my brother and it's come back on the wrong way after he took it apart to clean it before returning it.

Your brother is tacking the piss , surely ? ?

[John Rainford]

Photos of my clutch and sprocket.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

[spudulike]

The drum looks a little past it but not enough to give any jumping of the chain  or any other issues. The clutch springs look OK as does the friction part of the clutch shoe. Now that is a bit strange from the description of revving in the cut but the chain not spinning and would have expected bluing of the metal if the clutch was actually slipping.

Back to the drawing board Perhaps time for a vid!

Edited January 19, 2020 by spudulike

[bmp01]

I can't see any pictures,  just minture no entry symbols ??? 

If all the parts  look ok, could it be the inside of the drum is oil or grease coated ? Too much grease on the clutch bearing ? Oil pump leaking?

 

How long have you been sharpening chains, have you got the raker depth correct (not too deep)?  Picture of the saw chips ? (But this type of problem would cause the drum to over heat. ... and drum isn't blue (hot) so...)

 

[John Rainford]

Not sure what happened to the photos, they uploaded okay and were there for a while and then disappeared. There is some grease inside the drum so I will remove all of that. I,ll check the oil pump. I will put the saw back together when I have some free time at the end of the week and see if I can upload a video. I did try the saw with a couple of different chains which I had sharpened and checked the raker depth. Chain sharpening does seem to be a bit of an art and although I don't seem to be able to sharpen to the level of a new chain, I can get them reasonably good. When I post the video I will show the chip size. Maybe this one will still be going on until 2021 spud.