Stihl MS211/C problem with power in the cut

[Sawchip]

9 hours ago, John Rainford said:

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.

Pics are still there for me . (Edit..were at time of post..not now as of 7 pm mon 20th, odd . ) . Another thing to look at in the list. Check over the threads inside the clutch itself and the condition of the threads on the crank end.

Edited January 20, 2020 by Sawchip

[John Rainford]

I have taken a short video of my saw attempting to cut, but failing. I will upload it tomorrow, or rather my son will. Over the weekend my brother came over. He recently bought a Stihl MS 211, the same model as my saw, but 10 years younger. I asked him to bring it with him so that we could do a few basic checks. The first thing I did was to try his new bar and chain on my saw. It cut through a thin branch about 2 inches in diameter, but would not cut through the much bigger log I have been using for test cuts, which is about 9 inches in diameter. Next I tried swapping the air filter and muffler. I noticed that the engine sounded smoother running on idle, but it would still not cut . So i'm thinking that the  issue I have is not to do with the chain, bar, muffler or air filter. I did notice that when I start pulling on the throttle, the chain does not start moving until I have engaged the throttle about half way, There is also a lot of white smoke emerging from the exhaust when I engage the throttle. If I just let the saw idle there is no smoke. There always seems to be oil on the muffler back plate and underneath the muffler when I remove it after running. I'll upload the video when my son is here on Tuesday. 

[bmp01]

Chain will start to run dependant on engine speed (so not directly related to throttle position). Presumably you are comparing with the newer saw ? Are you saying there is more movement in throttle trigger before the saw responds (wear in the throttle linkage)? Or you need more engine speed before the chain moves (possible clutch issue) ?

Either get agreement or wait until your brother is not watching then borrow the complete carb off his saw and try it on yours ! Taking known good parts and swapping them onto your saw is a sound way to diagnose issues. Complete clutch assy ought to be right up there to try as well.

 

Hope that video makes an appearance soon, Feburary is looming...

Edited January 28, 2020 by bmp01

[spudulike]

Does the throttle open the carb throttle plate fully? If you hold the throttle open (on the bench, air filter off), you can try to open the carb up further with the linkage plate on the carb where the throttle rod joins the carb and if it does open further then the throttle rod is bent or there is wear in the linkages.

[bmp01]

13 hours ago, spudulike said:

......... throttle rod is bent or there is wear in the linkages.

Its a weird setup on these... the link is made to twist when you pull the trigger, the link is bent into a shape so that it acts as a cam which pushes on the carb lever. Twisting the link can take out play....

The wire link wears, the nylon block on the carburettor arm wears and the throttle rod can become dislodged from its location in the handle, then you only get half throttle movement.

My favourite hate is the cover for the throttle trigger with its protruding piece of plastic that keeps the linkage located in the handle - it's often broken off during reassembled. Result is notchy, half throttle movement. There have been several threads on here about this, new cover fixes the problem until the next time its taken apart and subsequently broken.....

 

[John Rainford]

I have uploaded the video, had to wait for my flu ridden son's computer skills, hence the delay. When I  start to engage the throttle , the engine revs increase as my finger pulls on the throttle trigger, but the chain does not move until I have pulled the throttle trigger half way back. 

 

Many thanks to spudulike, bmp01 and sawdust for helping me with this. I did think of swapping my brothers clutch and carb , but I didn't want to mess about to much with his new saw. I'll do as spud says and test  the carb and throttle linkage. That linkage to handle was a right pain when I reassembled the saw. It dropped out when I was dismantling the saw, so I didn't know how to reassemble it. I tried every possible thing I could think off, before realising that the linkage has to be forced under that little bit of plastic on the handle. No wonder they break, it's a terrible design. In the video commentary I use the word choke instead of throttle, so please be aware of this. This evening I spent an hour practising chain sharpening and studied the teeth before and after, using a magnifying glass. I noticed that the top of the tooth wasn't as sharp as I thought it would be, so started looking in to why this might be. At the risk of appearing foolish, I discovered that the files I have been using recently are 4.5 mm instead of the correct 4 mm size for my chains. I have no idea how this happened, but whatever the reason, it did. My calculations if accurate, mean that the files I have been using are 12.5% to big. Could this mean that the files are to big to get under the top part of the tooth to sharpen it ? Could this be why my chains are not cutting very well ?    I am a bit concerned about the amount of white smoke being omitted from the exhaust. 

 

ill try some new fuel with an accurate 50 : 1 fuel/oil mix to see if that makes a difference. Maybe the chain if not sharp on the top part of the teeth, is forcing the engine to work harder and overheat. I will get some 4 mm files and resharpen my chain, paying careful attention to the top part of the tooth to see if it comes out sharper. I had noticed that the saw chips coming from the saw immediately after sharpening were still very small, you may be able to see this in the video. Anyway, take a look and see what you think, and once again thanks for your help and knowledge sharing.

[Stubby]

14 hours ago, John Rainford said:

I have uploaded the video, had to wait for my flu ridden son's computer skills, hence the delay. When I  start to engage the throttle , the engine revs increase as my finger pulls on the throttle trigger, but the chain does not move until I have pulled the throttle trigger half way back. 

 

Many thanks to spudulike, bmp01 and sawdust for helping me with this. I did think of swapping my brothers clutch and carb , but I didn't want to mess about to much with his new saw. I'll do as spud says and test  the carb and throttle linkage. That linkage to handle was a right pain when I reassembled the saw. It dropped out when I was dismantling the saw, so I didn't know how to reassemble it. I tried every possible thing I could think off, before realising that the linkage has to be forced under that little bit of plastic on the handle. No wonder they break, it's a terrible design. In the video commentary I use the word choke instead of throttle, so please be aware of this. This evening I spent an hour practising chain sharpening and studied the teeth before and after, using a magnifying glass. I noticed that the top of the tooth wasn't as sharp as I thought it would be, so started looking in to why this might be. At the risk of appearing foolish, I discovered that the files I have been using recently are 4.5 mm instead of the correct 4 mm size for my chains. I have no idea how this happened, but whatever the reason, it did. My calculations if accurate, mean that the files I have been using are 12.5% to big. Could this mean that the files are to big to get under the top part of the tooth to sharpen it ? Could this be why my chains are not cutting very well ?    I am a bit concerned about the amount of white smoke being omitted from the exhaust. 

 

ill try some new fuel with an accurate 50 : 1 fuel/oil mix to see if that makes a difference. Maybe the chain if not sharp on the top part of the teeth, is forcing the engine to work harder and overheat. I will get some 4 mm files and resharpen my chain, paying careful attention to the top part of the tooth to see if it comes out sharper. I had noticed that the saw chips coming from the saw immediately after sharpening were still very small, you may be able to see this in the video. Anyway, take a look and see what you think, and once again thanks for your help and knowledge sharing.

Are you using a file guide/plate ? This will hold the file 1/5th of its diameter above the top plate of the cutter which is were it is supposed to be . Some people can do it " free hand " but if not use an Oregon guide or similar ......Edit . Having just watched the vid it seems to be " 4 stroking at about half revs which might be too rich ? Also apart from running shit the chain seems to be bouncing off the depth gauges . You need to take them down every 3rd or 4th sharpen .. Also chain  looks to be too tight ...

Edited January 31, 2020 by Stubby

[spudulike]

Right, two issues, the main one is that the saw just isn't hitting top revs as it should - I reckon about 6000rpm instead of around 13000rpm.

This could be caused by: -

1) Throttle not opening the carb fully - On the bench - just get the top cover off, hold the throttle open and see if you can get to the side of the carb and try to open the carb more with the bit the throttle rod pushes in to.

2) Choke is partially on - take the air filter off and see if the choke is fully off - that is it is not covering the bore but is parallel to the carb bore for maximum air flow.

3) Check the air filter isn't blocked - you could try running the saw without it - nylon mesh air filters can look very clean and be completely plugged.

4) Carb settings - should be 1+1 turns out. You could try turning the H screw in to see if the saw top revs increase as they should.

5) It is possible the high speed check valve is faulty but this would kill the idle - your saw sounds like the H screw is 3 turns out hence the smoke and poor revs.

6) I have seen faulty coils do this but usually check everything else and change the coil as a last option as they are a bit £££££ Try not to go aftermarket as they are more fragile.

The other issue is that your chain should be chipping better than that and looks pretty blunt - this isn't the main issue, not hitting the power band is the issue!

 

[bmp01]

Picture paints a thousand words, video even better.

In addiion to whats been said it looks like by the end of your demo the saw wouldnt reach 'high' revs out of the cut... it started out reving piss poorly but by the end the engine is labouring so badly it hardly has enough power to turn the chain even when its not cutting. I could be wrong, cant tell what you are doing with the throttle but the sound says its trying but can't do it - like the chain brake is part locked on, or the chain in is exceptionally tight. Just look how quick the chain comes to a halt,  it's almost locked up... 

 

If you repeat that exercise and turn the engine off, can you turn the chain by hand? Hot is it?

 

I totally agree with Spuds view but I'd say you've got some sort of chain or chain brake issue too.

 

Oh and the choke mechanism on these is on a par with the thottle linkage.... With age they jam and/or break.

 

 

[peatff]

It looks like a 171 I did at the farm. It was dying in the cut just like that and it had a carb kit fitted but was still the same till I raised the metering lever a bit then it was all good again. Your chain is having problems as well, I've seen sharper toenails.