Stihl 361 Clutch Drum problem

[smaho831]

Hello all, I've been learning from this thread for years and finally have a question that I can't find an answer here (or anywhere else).

Anyway, I am rebuilding a 361 that I acquired. The story is that it got run over by a big batwing brush mower.... It was pretty bead up and needed a lot of plastic, but I was able to start it and it ran well and had good compression. I just got done replacing the handle/tank, chain brake handle, main handlebar, and the clutch cover. The clutch drum didn't seem to spin as freely as it should, but. I started it and I ran half a tank of fuel through it anyway without any problems.

I investigated the clutch drum further and found that the bottom of the drum was rubbing on the oil pump and crankcase... I tried the clutch drum from my 360 pro and had the same issue. I am out of ideas, does anybody else have any?

 

[Chevboy0167]

My first thoughts would be the crankshaft got smacked hard on that side to the point of moving it and shoved it in farther. The more time and money consuming option would be to tear it all down and replace all bearings and seals. In other words, re-center the bearings on the crank and replace seals just because yer there.

Or.... sand down the clutch drum edge on a belt sander or other similar flat sander surface. Move the drum in a circular or figure 8 motion to remove the same amount of material on all sides evenly. Just remove a bit and test fit then repeat as needed until the drum no longer drags. Remove all burs on both sides of drum before final assembly.

Be mindful not to remove too much as to keep the shoes in full contact with said drum and help with cooling. The more material removed, the less heat can be dissipated when less material is present.

 

[drf255]

Did you install the washer behind the clutch?

An 1125 clutch drum is deeper than an 1128 drum. An 1125 drum will rub for sure, the 361 uses the same clutch and drum as the 1128 (044/46/461) models. The 360 drum upgrade for the 036 isn’t the same drum as the 440 like most think, the bearing is the same though.

If the drum bearing is bad, the drum will flex forward and do that to the oil pump as well.

Let’s see some assembly pics. And your worm gear.

 

[TLG]

I don't see the oil pump worm with the drive wire sticking through the drum slot. You are missing that for sure. They will use up some area and move drum outward.

Sent from my XT1635-01 using Tapatalk

 

[Junkwrencher]

Hello all, I've been learning from this thread for years and finally have a question that I can't find an answer here (or anywhere else).

Anyway, I am rebuilding a 361 that I acquired. The story is that it got run over by a big batwing brush mower.... It was pretty bead up and needed a lot of plastic, but I was able to start it and it ran well and had good compression. I just got done replacing the handle/tank, chain brake handle, main handlebar, and the clutch cover. The clutch drum didn't seem to spin as freely as it should, but. I started it and I ran half a tank of fuel through it anyway without any problems.

I investigated the clutch drum further and found that the bottom of the drum was rubbing on the oil pump and crankcase... I tried the clutch drum from my 360 pro and had the same issue. I am out of ideas, does anybody else have any?

View attachment 898740View attachment 898741View attachment 898742

In the posted pictures the drum is a spur type. Is this OEM, I zoomed and can only see 3/8 zZ. If that drum is aftermarket, they are notorious for being out of dimension and out of round. And yes, do install the clutch scatter shield sometimes called a washer.

 

[Junkwrencher]

In the posted pictures the drum is a spur type. Is this OEM, I zoomed and can only see 3/8 zZ. If that drum is aftermarket, they are notorious for being out of dimension and out of round. And yes, do install the clutch scatter shield sometimes called a washer.

 

[HarleyT]

Put up a pic of the worm drive sitting in place over the pump.

 

[smaho831]

Thanks so much for all the advice everybody!

The Drum is an OEM drum 1125/04B. I did have the worm gear as well as the washer behind the clutch installed. However, I did find the problem. I took the flywheel off and sure enough... the crankshaft moved. I am surprised that this isn't causing any other symptoms... I don't hear the bearings whining or anything.

Would it be possible to press the shaft back into position? I have a press in the shop if it is.

Is there any reason not to simply sand the drum down (or use the lathe) as Chevboy0167 suggested?

I've never cracked the crankcase on one of these saws, but

Thanks again for all the help!

​

 

[arto_wa]

Running a saw saw with the crank off-centered in the crankcase may or may not have caused internal damage, depending on how much it was off-centered and how long you ran it?

The crank can not be centered properly without removing the cylinder (center it, measuring with a feeler gauge), if it was my saw I would just split the case and inspect all before deciding what if any parts need replacing.

Or as quicker alternative, remove cylinder & center the crank with a press or ?, reassemble & take your chances.

 

[HarleyT]

I found this on youtube.
I think the guy drinks a little too much coffee...

 

[HarleyT]

First off, remove the flywheel and clutch first,

I haven't watched the whole thing, but it looks funny.

 

[pioneerguy600]

I found this on youtube.
I think the guy drinks a little too much coffee...

High on helium.