Stihl 041 drum differences? Need help please.

[dsell]

The clutch springs are not the problem. The drum should turn easily without turning the clutch in your bottom picture. If not, then you are pressing the clutch against the drum causing them to turn together. There has to be clearance between the clutch spider and the drum after the clutch is tight. I'm just guessing, but #23 probably adds the distance you need to the bearing surface of the crankshaft.

 

[Patrick1903]

The clutch springs are not the problem. The drum should turn easily without turning the clutch in your bottom picture. If not, then you are pressing the clutch against the drum causing them to turn together. There has to be clearance between the clutch spider and the drum after the clutch is tight. I'm just guessing, but #23 probably adds the distance you need to the bearing surface of the crankshaft.

So you think that the washer, number 23 would ride against the outside of the needle bearing (which is inside the drum) and the clutch spider spider would spin against that washer?? Just wanting to make sure I understand it correctly. That was the configuration that I had before I added washer number 26 in addition to washer number 23. Washer number 23 seems to fit inside the recess of the drum, flush with inside recess of drum. So it does not provide any standoff from the clutch.

OK - I just got back from the garage. I think I have figured something out that could be causing the problem (I always think I've discovered the problem but it doesn't always (or normally???!) turn out to the be real problem).

The pin that is called for in my setup (rim sprocket) - is 10mm long. The current pin in there is 13.59mm. See picture of the pin, with black sharpie marking where 10mm would be (measured from the left to right).


Here's what may be happening - tell me if this makes sense or not!
1) Too long of pin is in the washer that holds it - that is pressed against the worm gear assembly in order for the washer to be flush against the worm. When I do that, the pin pushes out as far as it can b/c it is bottoming out inside the oiler hole. So now a longer then normal piece of pin is sticking out.
2) Next the sprocket and drum go over the washer, and the pin inserts into the drum spline. Since the pin is too long (coupled with the potential that there is a broken off pin in the hole of the drum) - the drum sits out farther than it should from the oiler (i.e. closer to the clutch). This results in the washer (#23) sitting inside the drum recess, versus sitting proud of the recess. Since it is not proud of the recess, the clutch spyder tightens directly against the clutch drum - always turning the drum/sprocket.
The other adverse affect here is that the drum is no longer in the plane of the crankcase - i.e. it's crooked. Could this be why I have extra vibration and thinking the crank was bent, when I briefly ran the saw a couple months ago? See pictures.



3) As an experiment, if I press the washer & pin first into the drum, to make it flush with the drum, then set it onto the crank, the washer doesn't ride flush against oiler assembly/crankcase. It now will allow the washer, #23, to sit proud of the clutch drum, which should then provide standoff from the clutch. See pictures.This would also result in an off balance situation for the entire assembly, I believe.



So I think I need a new pin (or grind this one down). And it seems the drum should be replaced (Really seems to have a broken pin there, plus the opening should be a hole, not a gaping tear. See pic.

 

[dsell]

yes, this is what I was thinking. I don't know what to tell you on your oiler pin, but I think you are on the right track of looking for clearance issues. If it sticks out more than it should, then yes it will lock the drum to the clutch.

So you think that the washer, number 23 would ride against the outside of the needle bearing (which is inside the drum) and the clutch spider spider would spin against that washer?? Just wanting to make sure I understand it correctly. That was the configuration that I had before I added washer number 26 in addition to washer number 23. Washer number 23 seems to fit inside the recess of the drum, flush with inside recess of drum. So it does not provide any standoff from the clutch.

 

[Patrick1903]

yes, this is what I was thinking. I don't know what to tell you on your oiler pin, but I think you are on the right track of looking for clearance issues. If it sticks out more than it should, then yes it will lock the drum to the clutch.

So you think that the washer, number 23 would ride against the outside of the needle bearing (which is inside the drum) and the clutch spider spider would spin against that washer?? Just wanting to make sure I understand it correctly. That was the configuration that I had before I added washer number 26 in addition to washer number 23. Washer number 23 seems to fit inside the recess of the drum, flush with inside recess of drum. So it does not provide any standoff from the clutch.

Ok great. In the interest of time, I'll try to cut the pin down to spec and see if that solves the problem. The X factor also could be if there is pin remant left in the clutch drum. Here's what a new drum looks like, which you can compare to the final pic in my post #22.

 

[dsell]

There's no pin broke in your drum. It's just a slot on that one. Maybe the pin isn't going in the oiler completely?

 

[dsell]

That drum is not listed for the 041. Maybe that's the problem.

 

[Patrick1903]

There's no pin broke in your drum. It's just a slot on that one. Maybe the pin isn't going in the oiler completely?

Ok . I thought the bright silver circular piece was part of a pin. I circled that in red below.

in either case, I cut the pin down to 10mm,per the IPL part. It keeps everything nice and square in there, it seems. I’m still not able to turn the drum independent of the clutch. As I get to the last couple threads tightening the clutch down, by hand even before with the wrench, I can hear a show dragging on the drum. So whether or not that is my issue, or if it’s from lack of stand-off, which I think I resolved with the shorter pin, I don’t know. But it seems like I need to try to not have the shoe drag when I put the clutch on. Thoughts?

 

[L34]

Don't ask me the details as I can't remember.
But I put a rim drive on dad's 040.
I had to do some grinding here and there for clearence.
On the end of the rim drives I believe.
Or it would bind up when done up tight.

 

[Patrick1903]

It seems like I should try to switch this thing to the spur drive. On my other thread about this saw someone also thought the Oregon 18200 Powermate that's on there is compatible. I will try to call Oregon tomorrow and see if they can shed any light. As was pointed out in the other thread, Jack's Small Engine Repair shows the 18200 Oregon p/n associated with the 041FB, after serial number 5664891 (which is where this saw is, after that (1976 model).

According to the IPL - I would need to get items #17, 18, 20. I bought #26 last week, apparently in error, so I don't need that at least.



I suppose I may as well replace #19, the needle bearing. I have already greased the one that was there. I didn't clean it first. I suppose I can try cleaning it in gas and seeing what it looks like. Let me start pricing this stuff...and put a fresh charge in the parts cannon.

 

[Patrick1903]

I've hit a roadblock and am totally out of ideas at this point. I think perhaps the clutch is not tightening onto the crankshaft shoulder but instead is tightening against the drum (or some other part connected to drum, i.e. the washer and bearing), thereby locking the entire clutch and drum/sprocket assembly together. And I think that is because the crankshaft shoulder is not far enough out - or really - the drum assembly is too far out - thereby making the crank shoulder not catching

I replaced the clutch springs, then I bought a replacement clutch and drum (used) Oregon 32060 (matches the part from Post #26 table). Reassembled everything, but when I tightened clutch down into drum - it's not separating from drum. I cannot turn the drum separate from the clutch. To be sure, I put the B&C on anyway, try pulling chain through, and it's doing exactly the same - turning the crank along with it.

I would love to see an 041 that works correctly and see the setup. The only other x-factor from what I have installed is the two parts listed above - #17 and 24. They appear to be different thicknesses, and the thicker one apparently does not have the "flange" shape. I think getting rid of the flange would help - it would allow the bearing to slide closer to crankshaft, which would then allow the spacer ring to go against the crankshaft shoulder (instead of the spacer pressing against the outside of the bearing). I can't seem to find the other one for sale online. The two p/n are: 1110 030 7502 and 1110 030 7503. I am not sure which is which.

one last thought.I suppose I could try to find a shorter needle bearing. I have two of them for the two different drums so figured I should stick with that one.

This thread appears to be the same issue, starting witih #24.
https://www.arboristsite.com/threads/stihl-041-av-fb-rebuild-restoration.350742/post-7504479
Anyone? @ReliableRust maybe? You fought with a similar issue a year ago.

Here are my latest pics of this never ending project.
First one shows the bearing protruding past the shoulder of the crank.
Rest are my configuration.

 

[Patrick1903]

I've hit a roadblock and am totally out of ideas at this point. I think perhaps the clutch is not tightening onto the crankshaft shoulder but instead is tightening against the drum (or some other part connected to drum, i.e. the washer and bearing), thereby locking the entire clutch and drum/sprocket assembly together. And I think that is because the crankshaft shoulder is not far enough out - or really - the drum assembly is too far out - thereby making the crank shoulder not catching

I replaced the clutch springs, then I bought a replacement clutch and drum (used) Oregon 32060 (matches the part from Post #26 table). Reassembled everything, but when I tightened clutch down into drum - it's not separating from drum. I cannot turn the drum separate from the clutch. To be sure, I put the B&C on anyway, try pulling chain through, and it's doing exactly the same - turning the crank along with it.

I would love to see an 041 that works correctly and see the setup. The only other x-factor from what I have installed is the two parts listed above - #17 and 24. They appear to be different thicknesses, and the thicker one apparently does not have the "flange" shape. I think getting rid of the flange would help -

Ok, I think this post from 10 years ago indicates there’s a flat washer without that flange/collar that may be the answer. Cross referencing back to that thread.
maybe p/n
1110 030 7500


Post in thread 'What happened here Stihl?'
https://www.arboristsite.com/threads/what-happened-here-stihl.207536/post-7710152

 

[hotshot]

Yup, that set up won’t work. The needle bearing has to sit below the crank step.

Just grind the shaft flange off the 7501 cover washer you have, until you find a -7500. Pull out the pin first.

The 032 I worked on had the wide collar PTO side bearing installed & I ended up taking material from both the plastic oil pump gear kit & the AFM 18200 Oregon sprocket end to get the correct clearance.

Thinking it was 0.050” total removed to get bearing end to shaft step clearance of 10 thou play, and also had to shorten my drive pin after fitting the sprocket.

Four variables on the 032, the x2 different PTO bearings, x3 oil pump gears (all the same part nos), x2 cover washers then mix in the AFM drums.

Even with publishing tech bulletins, Stihl sucks at documenting their part revisions & assemblies compatibility, just look at their 056 and 066 ignition coils & FW abortions.

 

[Patrick1903]

Yup, that set up won’t work. The needle bearing has to sit below the crank step.

Just grind the shaft flange off the 7501 cover washer you have, until you find a -7500. Pull out the pin first.

The 032 I worked on had the wide collar PTO side bearing installed & I ended up taking material from both the plastic oil pump gear kit & the AFM 18200 Oregon sprocket end to get the correct clearance.

Ok thanks for confirming for me. My only concern is- without that flange, which slides into the ID of the drum, that cover has nothing holding it concentrically around the crank, except that pin. Since the crank is not tight to the ID of the washer. Would that put excessive pressure on that pin? Just curious. Or maybe I don’t need to take flange all the way back. I’ll have to measure and grind and see. Thanks!

 

[L34]

As I said above I had to do some grinding on dad's 040.
It may of been that flange lip.
Everything still worked ok.

 

[Patrick1903]

As I said above I had to do some grinding on dad's 040.
It may of been that flange lip.
Everything still worked ok.

OK awesome - thanks everyone for feedback and help. Problem solved after getting rid of most of that flange on my oil pump cover/washer part. I used a flat file to take it down most of the way. I wanted to see if I could get away with leaving a little bit of a flange so that that there would be some remaining material to slide into the clutch drum/sprocket. So that worked and I could tighten the clutch down and still spin the drum - success finally! The needle bearing is really close to the shoulder but the spacer washer seemed to be in solid contact with the shoulder and not pressing against the bearing. Pic below, and video of me spinning clutch drum with clutch tightened down.


View attachment trim.61BF3B42-86EE-469F-ADDD-B2E4B17F2CD9.MOV