MS200T clutch side crank seal question

[MattG]

Hi folks,

I've searched a few MS200T crank seal threads and not quite found the information I need. My question is quite specific, so I thought I'd post a new thread.

The story is that about a month ago I bought an old and broken MS200T from ebay. This was basically as a rebuild, "learn about saw mechanics" project. When I first got it, I found that it fires from cold reasonably soon, but runs erratically, sometimes it will rev high and cut fine, other times it will die half way up the rev range. Hand in hand with this, the compression gauged through the pull rope isn't that great, and sometimes hot starts are very bad.

So since it's a rebuild/learning project, I've decided tear it down, renew anything obvious wrong, and change the crank seals. I've now got the saw stripped so that only the cylinder/jug is still on, and the crankcases still together. Now it's stripped down I'm wondering if the last guy either got halfway through a rebuild, or got the rebuild wrong.

What looks WRONG to me is the current state of the crankseal on the clutch side. I haven't moved it yet, but the position of it's outside face looks wrong. Instead of it being flush to the main crankcase housing, it's flush with the tops of the 3 lugs that the oil pump mounts against. In other words it's as if it's hanging out of the housing by 2 or 3 millimeters. This seems bad to me - surely after the seal is correctly pressed in, it should be flush to the housing? That's how I've always done seals - on cars and motorbikes in the past. Additionally, there's evidence of very slight marking to the edge of this seal, as if the last guy has started trying to pry it out, then gave up the job.

So my question is - should the clutch side seal on MS200T be pressed flush to the housing or to the tops of the lugs?

thanks
Matt

 

[angelo c]

Matt, good luck with the rebuild.
Make sure the stalling was NOT the carburetor , which the pump shaft is known to wear and cause erratic throttle behavior.
Maybe post a pic of the seal in question...

 

[lone wolf]

You need to vac and pressure test it and pinpoint the problem.

 

[big t double]

Top of the lugs is correct.

 

[MattG]

Matt, good luck with the rebuild.
Make sure the stalling was NOT the carburetor , which the pump shaft is known to wear and cause erratic throttle behavior.
Maybe post a pic of the seal in question...

Thanks, I was going to look at the carburretor, too. Just thought of looking at the diaphrams, I didn't know that the pump shaft could cause issue too...

 

[MattG]

You need to vac and pressure test it and pinpoint the problem.

I know that's the best approach, but I'm quite keen on learning to strip the whole saw - as a learning exercise. Need to get a vac gauge sometime though.

 

[MattG]

Top of the lugs is correct.

Really? I've only ever changed oils seals on cars and bikes in the past, but on them I always thought you pressed till flush with the main housing. I'm just surprised because if you leave them flush with the lug tops then it's like they hanging out by 2 mil or so.

 

[angelo c]

Thanks, I was going to look at the carburretor, too. Just thought of looking at the diaphrams, I didn't know that the pump shaft could cause issue too...

other then the carb and the seals( aging Bakelite) very little goes bad with that saw and they are put threw hell daily. a remarkably durable saw. most fail because NOTHING get serviced on the saw and it just keep running...and running...and you forget the thing needs to have its AV bushings replaced and a hose or so every ..oh IDK like every 70 or so thousand dollars worth of limbs dropped...

 

[lone wolf]

I know that's the best approach, but I'm quite keen on learning to strip the whole saw - as a learning exercise. Need to get a vac gauge sometime though.

Well you really should rip it down and do it right , otherwise you will waste more time and money throwing the wrong parts in it. We can help I know them well, start stripping it and buy a Mitivac 8500 it does vac and pressure.

 

[MattG]

other then the carb and the seals( aging Bakelite) very little goes bad with that saw and they are put threw hell daily. a remarkably durable saw. most fail because NOTHING get serviced on the saw and it just keep running...and running...and you forget the thing needs to have its AV bushings replaced and a hose or so every ..oh IDK like every 70 or so thousand dollars worth of limbs dropped...

Yeah, I know what you mean with STIHL equipment - it's very tough. I've got an old ms341 (from ebay again). I fixed up a few things like upgrading the oiler and a basic service, but I haven't touched the engine and it runs brilliant!

 

[MattG]

Well you really should rip it down and do it right , otherwise you will waste more time and money throwing the wrong parts in it. We can help I know them well, start stripping it and buy a Mitivac 8500 it does vac and pressure.

Yeah, cool. No problems stripping it and rebuilding it... But I'm just puzzled about the issue I mentioned in my original post. That is, should the new seals be pressed in so they are flush with MAIN HOUSING or the TOP of the oiler locating lugs? big t double says to the top of the lugs - but that's contrary to my previous experience with larger engines. What's your view? This thing is the main thing I'm puzzled over. And looking at the saw it looks like the last guy attempted a rebuild and messed it up.

 

[lone wolf]

Yeah, cool. No problems stripping it and rebuilding it... But I'm just puzzled about the issue I mentioned in my original post. That is, should the new seals be pressed in so they are flush with MAIN HOUSING or the TOP of the oiler locating lugs? big t double says to the top of the lugs - but that's contrary to my previous experience with larger engines. What's your view? This thing is the main thing I'm puzzled over. And looking at the saw it looks like the last guy attempted a rebuild and messed it up.

Post a good pic of it for us . If it passes a test it works , it could be out by a tiny bit and still work fine . I wont know until I see how much you are talking about, if one side is out more then the other it is out of whack a bit but it may still work ,depends how much.

 

[big t double]

Really? I've only ever changed oils seals on cars and bikes in the past, but on them I always thought you pressed till flush with the main housing. I'm just surprised because if you leave them flush with the lug tops then it's like they hanging out by 2 mil or so.

Yes I'm positive. Here's the actual Stihl seal press tool for the 200t's. Once you hit the lugs it don't press any further. I know you don't believe me but it's true.

 

[MattG]

Post a good pic of it for us . If it passes a test it works , it could be out by a tiny bit and still work fine . I wont know until I see how much you are talking about, if one side is out more then the other it is out of whack a bit but it may still work ,depends how much.

Ok, I'm at work now, so I can't. I'll try to get one done tonight and attach it.

 

[MattG]

Yes I'm positive. Here's the actual Stihl seal press tool for the 200t's. Once you hit the lugs it don't press any further. I know you don't believe me but it's true.
View attachment 428610

A ha! No thanks! I believe you now and I'm smiling. Like you say when you're on the lugs it can't go no more.

I appreciate you have the right tools, so it's pretty easy for you to demonstrate. Thanks a million for taking the time. I'll try to send a few pics of my work tonight anyway.

Thanks again, fellas

 

[angelo c]

Yes I'm positive. Here's the actual Stihl seal press tool for the 200t's. Once you hit the lugs it don't press any further. I know you don't believe me but it's true.
View attachment 428610

Hey Big T,
How much was that "socket" er press tool specifically for 200t's ?

 

[big t double]

there really is no retail price on the stihl tools. I would take that part number to your dealer and see what he'd sting you...id charge 12 if you bought it from me. and yea, ive used actual sockets on 200t seals and it never fails ill get burley with it and crack at least one of those stupid clay/bakelite things...so I broke down and bought the press arbor.

 

[angelo c]

there really is no retail price on the stihl tools. I would take that part number to your dealer and see what he'd sting you...id charge 12 if you bought it from me. and yea, ive used actual sockets on 200t seals and it never fails ill get burley with it and crack at least one of those stupid clay/bakelite things...so I broke down and bought the press arbor.

usually pays off to avoid the "cheaper" route in the long run...
once you have the "right" tools you tend to want to use them more often too.

 

[MattG]

Hi again guys

Got back from work couple of hours ago and got a piccy. Here you can see the seal hanging out a bit, but flush with the top of the lugs.

But as big t double says, this must be how STIHL want them doing, since the press tool fouls on the lugs...

I'll not use the special tool and will try to by with patience, a sockets perhaps some tape to build a taper up to get the seal past the crank shoulder, without tears.

Since I've not got a vac gauge yet, I'm gonna guess that splitting and re-sealing the crankcases might be wise, since I've got it all cleaned up and dismantled. Again it's something I used to do with motorbikes so I guess it should be fairly straightforward, but if you guys have any more advice then feel free to pass it on!

Matt

 

[lone wolf]

Hi again guys

Got back from work couple of hours ago and got a piccy. Here you can see the seal hanging out a bit, but flush with the top of the lugs.

But as big t double says, this must be how STIHL want them doing, since the press tool fouls on the lugs...

I'll not use the special tool and will try to by with patience, a sockets perhaps some tape to build a taper up to get the seal past the crank shoulder, without tears.

Since I've not got a vac gauge yet, I'm gonna guess that splitting and re-sealing the crankcases might be wise, since I've got it all cleaned up and dismantled. Again it's something I used to do with motorbikes so I guess it should be fairly straightforward, but if you guys have any more advice then feel free to pass it on!

Matt

Did you find all 6 screws in the case the hidden one under the rubber plug?