MS201t Problem

[SteveSr]

The one thing that he hasn't changed is his AM P&C which could have issues with machining tolerances leaving too small a squish band and too high a compression.

This brings up another reminder... Someone recently posted a pic of an OEM Stihl top handle jug that a mysterious slot milled above what I believe was the intake port. I believe that this was done as a compression release to make it easier to start the saw. @lone wolf , have you seen this before and could it be the issue with the AM jug if it didn't have this extra machining?

 

[lone wolf]

The one thing that he hasn't changed is his AM P&C which could have issues with machining tolerances leaving too small a squish band and too high a compression.

This brings up another reminder... Someone recently posted a pic of an OEM Stihl top handle jug that a mysterious slot milled above what I believe was the intake port. I believe that this was done as a compression release to make it easier to start the saw. @lone wolf , have you seen this before and could it be the issue with the AM jug if it didn't have this extra machining?

I never saw the o

The one thing that he hasn't changed is his AM P&C which could have issues with machining tolerances leaving too small a squish band and too high a compression.

This brings up another reminder... Someone recently posted a pic of an OEM Stihl top handle jug that a mysterious slot milled above what I believe was the intake port. I believe that this was done as a compression release to make it easier to start the saw. @lone wolf , have you seen this before and could it be the issue with the AM jug if it didn't have this extra machining?

What a 201T or 200T jug?

 

[lone wolf]

The one thing that he hasn't changed is his AM P&C which could have issues with machining tolerances leaving too small a squish band and too high a compression.

This brings up another reminder... Someone recently posted a pic of an OEM Stihl top handle jug that a mysterious slot milled above what I believe was the intake port. I believe that this was done as a compression release to make it easier to start the saw. @lone wolf , have you seen this before and could it be the issue with the AM jug if it didn't have this extra machining?

I mentioned measuring the squish to him but I dont know if he checked it.

 

[SteveSr]

Was it a 201T or 200T jug?

I don't remember. Thought that you might know off the top of your head.

 

[ShermanC]

I have worked on small engines a long time, but I have come across a problem with a Stihl MS201t that has got me stumped.

The saw came to me in this in good condition, it wasn't too terribly dirty, the blade did seem to show signs of over tightening, but didn't seem to have too many hours on it. Anyway, I go to pull-start it and the engine turns, but extremely hard (It's like trying to start a much larger saw without first pushing in the compression release). My first thought is that there is something wrong with the pull-start, but after removing it and inspecting it, there is no problem there. Pulled the chain cover, chain and clutch, no problems there.

So, I figure that the engine is partially seized.

So I install a new after-market piston, rings, and cylinder, and put it all back together, go to pull-start it again, and the same thing happens.

So, then I think, maybe, the saw got over heated and it seized the bearings in the crank and it only becomes an issue when it is under compression? So, I found a used crankcase (Complete lower end) online that upon inspection seemed to work just just fine, and installed the new piston, rings and cylinder on to it, put the saw together, tried to pull-start it, and the same thing happens.

So, I scratch my head, pull the spark plug, and tug on the pull-starter, and it pulls easily!

So, I think, maybe I put the piston in backwards? I pulled it apart again, and find that the piston was installed correctly.

I have gone through every thing that I can think of could possibly be the problem: pulled the spark arrestor, pulled the muffler, pulled the carburetor, intake manifold to no avail.

I have pulled everything off of the motor and tried to pull-starter and get the same results; it is to0 hard to pull to get the motor to turn without really holding it down, or locking it in a vice. But, if I pull the spark plug, it spins easily!

In other words, this saw has a totally different motor in it than what came to me, but I am having the same problem!

Any thoughts?

Ddogwood

 

[lone wolf]

Send me the damned thing so we can know what the hell is the problem . Also send the original Cyl .

 

[ShermanC]

The replies have been well thought out. My 2009 MS200T has had the same problem until it quit running. Compressions has been so tight. Stihl tech replaced the manifold but yet it would not run. I hate to spend more $ on it. It has served me 11 years with thousands of hours of work but the time has come to say goodbye. I'm trying to justify or reason doing a purchase of a MS201TC-M but money for equipment has been so scarce for a year or so. I just have to think through it some more.

 

[Nathan Graff]

The replies have been well thought out. My 2009 MS200T has had the same problem until it quit running. Compressions has been so tight. Stihl tech replaced the manifold but yet it would not run. I hate to spend more $ on it. It has served me 11 years with thousands of hours of work but the time has come to say goodbye. I'm trying to justify or reason doing a purchase of a MS201TC-M but money for equipment has been so scarce for a year or so. I just have to think through it some more.

Calling Lone wolf. owOOOOOOOOO!!!!!

 

[lone wolf]

 

[Ddogwood]

wh

So did you try pull starting with the whole clutch assembly off yet?

Yes, on a few occasions. No change.

 

[Ddogwood]

I never saw the o

What a 201T or 200T jug?

I have not checked the squish. Seeing as a compression test didn't show that it was high, I didn't think it necessary

Ddogwood

 

[Ddogwood]

The one thing that he hasn't changed is his AM P&C which could have issues with machining tolerances leaving too small a squish band and too high a compression.

This brings up another reminder... Someone recently posted a pic of an OEM Stihl top handle jug that a mysterious slot milled above what I believe was the intake port. I believe that this was done as a compression release to make it easier to start the saw. @lone wolf , have you seen this before and could it be the issue with the AM jug if it didn't have this extra machining?

It was doing the same thing with the original OEM P&C.

Ddogwood

 

[Ddogwood]

Do you suppose one or more clutch springs are weak & are allowing some contact with the drum even though the RPMs generated by pulling the start rope are very low? If that was happening, the chain trying to turn would create quite a drag.
Just a thought, & another wild stab!!

Now, that is something that I didn't think of. The clutch springs have not been replaced, but when the saw is running, the chain doesn't spin at idle and the clutch does seem to engage and disengage properly when giving it the gas. And, to answer Lonewolf's question, the sprocket is lining up with the oil pump properly. I have even tried pulling the saw with the clutch, sprocket and oil pump remove, and still have the same hard pull. So, I don't believe that the problem lies in the clutch, cover, chain, bar or oil pump. Nor, do I believe that the problem is in the pull-starter, flywheel, or in the air gap between the FW and ignition module, or in the exhaust. The only thing left would be some crazy problem with the carburetor or intake, but I don't imagine that this is the case. I am stumped.

 

[lone wolf]

Now, that is something that I didn't think of. The clutch springs have not been replaced, but when the saw is running, the chain doesn't spin at idle and the clutch does seem to engage and disengage properly when giving it the gas. And, to answer Lonewolf's question, the sprocket is lining up with the oil pump properly. I have even tried pulling the saw with the clutch, sprocket and oil pump remove, and still have the same hard pull. So, I don't believe that the problem lies in the clutch, cover, chain, bar or oil pump. Nor, do I believe that the problem is in the pull-starter, flywheel, or in the air gap between the FW and ignition module, or in the exhaust. The only thing left would be some crazy problem with the carburetor or intake, but I don't imagine that this is the case. I am stumped.

Send it! People want to know.

 

[Ddogwood]

Send it! People want to know.

Once the new ignition module arrives and I have the saw back together, I will think about the costs of sending the saw across country and back. It probably would have been cheaper for me to have just bought my customer a new saw, and a lot more gratifying to run this one over with my truck.

Ddogwood

 

[1hander]

sorry for your frustrations boss.. i read the entire thread...
i had a similar problem when i was rebuilding my 015L.. i crank case designs are different but the use of needle bearing mains is the same..

when i first got the saw, it ran ok..apart from low compression .. and i noticed that right at TDC it would get hard to pull over...almost get stuck for just a slit second when pulling over without the plug in it
with the plug in it, it would turn over but it was alot harder than it shoulda been, for a saw with 120psi compression.

1. sooo during the rebuild i took the piston pin out and found that the it was scarred right in the middle, this was part of the TDC sticking problem
also the small end of the conn rod was bent ever so slightly and causing binding in the wrist pin joint,
it was also causing the piston to rock sideways , compression would magnify the problem

2. after i got the piston and conn rod thing ironed out, i was putting iit back together and after i tightened the crank case bolts, i always put the starter on and pull to check for free movement,
and holy crap was it hard to pull...then free up ...then hard to pull..
what i found had happened is that the main needle bearings were not seated properly up against the washer that seperates the bearing and the seal.. so the crank was hitting the edges of the bearing faces
also because i did not properly seat and push the bearings all the way in... when i tightened the case bolts, it distorted and was causing the rollers to bind.. but the funny thing was thar without the
plug i really could not feel the binding at all...as soon as i put the plug in, it felt like pulling the piston through concrete
after reseating the bearings properly it was silky smooth again..

3. could be main bearings were damaged during install...but they are pretty tough on the 201T

4. on the 08s i rebuilt, i was getting a similar dragging during pulling on the starter...but only with the plug in.. on this it turned out to be.. the shaft that starter wheel spins on.. embled
without the plug, it would pull great.. but with the plug it felt super hard and almost gritty during the pull and i was not able to get a fast enough pull to start it..
turned out the bushing inside the rope wheel was super junked and was just wobbling enough with the resistance of the compression that it would bind up..
had to put a new bushing in it.

5. with needle mains..alignment of the main bearings is critical... or youll get binding under compression..
a. its possible that either the crank bearings are distorted,
b. not fully seated

6. my last theory is that crank cases are distorted and not aligning properly. after years of use and constant heat cycles the shapes of the cases will change
a. every thing is great until the cases are separated , this is when they would distort and will probably never go back to original shape and or alignment
b. with the cases no longer aligning properly, the opposite sides of the crank will never align properly and will cause binding in the crank needle bearings
but this would kinda be like #5

7. check the thickness of the cylinder head base gasket.. ive found that alot of times the replacements are no where near the same thickness as the originals
could be you just ended up with an overly healthy saw, try thicker base gasket maybe to lower compression.

8. is the replacement piston the same height as the original, alot of times designs change and the part will says ??????? replaces ??????? , when what it should say is superseded, not replaced
because the new part is not the same as the older one that it superceded.. case in point the piston for my 015L shows the replacement to be a newer version, but the one i had was not a roller wrist pin
the so called replacement has a roller bearing supporting the wrist pin.. which requires changing the connecting rod as well.. which i did do.. so my little 015L should last a very long time

9. is the crankshaft of the same specs, i mean is the stroke the same...again sometimes they change stuff on you..

distortion is part of the reason i avoid hammering at all cost when separating cases. i use the case splitter and or sometimes a heat gun or a minitorch.. and they slide right apart..
surprisingly enough even with a minitorch, ive never messed up a set of cases

i gotta tell you ...this one has me scratching my.. i know some of the things i posted have already been covered. but i wanted to list all my sits that applied,
you never know when something will jog a bolt loose and you have that eureka moment..
please keep posted if you figure this out.

 

[Ddogwood]

sorry for your frustrations boss.. i read the entire thread...
i had a similar problem when i was rebuilding my 015L.. i crank case designs are different but the use of needle bearing mains is the same..

when i first got the saw, it ran ok..apart from low compression .. and i noticed that right at TDC it would get hard to pull over...almost get stuck for just a slit second when pulling over without the plug in it
with the plug in it, it would turn over but it was alot harder than it shoulda been, for a saw with 120psi compression.

1. sooo during the rebuild i took the piston pin out and found that the it was scarred right in the middle, this was part of the TDC sticking problem
also the small end of the conn rod was bent ever so slightly and causing binding in the wrist pin joint,
it was also causing the piston to rock sideways , compression would magnify the problem

2. after i got the piston and conn rod thing ironed out, i was putting iit back together and after i tightened the crank case bolts, i always put the starter on and pull to check for free movement,
and holy crap was it hard to pull...then free up ...then hard to pull..
what i found had happened is that the main needle bearings were not seated properly up against the washer that seperates the bearing and the seal.. so the crank was hitting the edges of the bearing faces
also because i did not properly seat and push the bearings all the way in... when i tightened the case bolts, it distorted and was causing the rollers to bind.. but the funny thing was thar without the
plug i really could not feel the binding at all...as soon as i put the plug in, it felt like pulling the piston through concrete
after reseating the bearings properly it was silky smooth again..

3. could be main bearings were damaged during install...but they are pretty tough on the 201T

4. on the 08s i rebuilt, i was getting a similar dragging during pulling on the starter...but only with the plug in.. on this it turned out to be.. the shaft that starter wheel spins on.. embled
without the plug, it would pull great.. but with the plug it felt super hard and almost gritty during the pull and i was not able to get a fast enough pull to start it..
turned out the bushing inside the rope wheel was super junked and was just wobbling enough with the resistance of the compression that it would bind up..
had to put a new bushing in it.

5. with needle mains..alignment of the main bearings is critical... or youll get binding under compression..
a. its possible that either the crank bearings are distorted,
b. not fully seated

6. my last theory is that crank cases are distorted and not aligning properly. after years of use and constant heat cycles the shapes of the cases will change
a. every thing is great until the cases are separated , this is when they would distort and will probably never go back to original shape and or alignment
b. with the cases no longer aligning properly, the opposite sides of the crank will never align properly and will cause binding in the crank needle bearings
but this would kinda be like #5

7. check the thickness of the cylinder head base gasket.. ive found that alot of times the replacements are no where near the same thickness as the originals
could be you just ended up with an overly healthy saw, try thicker base gasket maybe to lower compression.

8. is the replacement piston the same height as the original, alot of times designs change and the part will says ??????? replaces ??????? , when what it should say is superseded, not replaced
because the new part is not the same as the older one that it superceded.. case in point the piston for my 015L shows the replacement to be a newer version, but the one i had was not a roller wrist pin
the so called replacement has a roller bearing supporting the wrist pin.. which requires changing the connecting rod as well.. which i did do.. so my little 015L should last a very long time

9. is the crankshaft of the same specs, i mean is the stroke the same...again sometimes they change stuff on you..

distortion is part of the reason i avoid hammering at all cost when separating cases. i use the case splitter and or sometimes a heat gun or a minitorch.. and they slide right apart..
surprisingly enough even with a minitorch, ive never messed up a set of cases

i gotta tell you ...this one has me scratching my.. i know some of the things i posted have already been covered. but i wanted to list all my sits that applied,
you never know when something will jog a bolt loose and you have that eureka moment..
please keep posted if you figure this out.

Thanks for all the great ideas. It seems that you've had some interesting fixes. The needle bearings binding at TDP has got me thinking. The only thing that stops me from tearing it apart again is that I have had this saw assembled with two different crank cases and two different sets of heads and pistons (the OEM set and the AM set) and I still have the same problem. I mean it is possible that the bearings in both crank cases are screwed up. And, I am hesitant to keep throwing more money and parts at this thing. I think that I will sit and stare at it for a few days and come up with a game plan on my next moves.

I do appreciate your input. Stay tuned....Page 8 coming soon.

Ddogwood

 

[1hander]

LO////well if you get tired of it, i wouldnt mind taking a swing at it some day.. keep us posted

 

[Ddogwood]

LO////well if you get tired of it, i wouldnt mind taking a swing at it some day.. keep us posted

Thanks.

 

[Bruiser1]

I have worked on small engines a long time, but I have come across a problem with a Stihl MS201t that has got me stumped.

The saw came to me in this in good condition, it wasn't too terribly dirty, the blade did seem to show signs of over tightening, but didn't seem to have too many hours on it. Anyway, I go to pull-start it and the engine turns, but extremely hard (It's like trying to start a much larger saw without first pushing in the compression release). My first thought is that there is something wrong with the pull-start, but after removing it and inspecting it, there is no problem there. Pulled the chain cover, chain and clutch, no problems there.

So, I figure that the engine is partially seized.

So I install a new after-market piston, rings, and cylinder, and put it all back together, go to pull-start it again, and the same thing happens.

So, then I think, maybe, the saw got over heated and it seized the bearings in the crank and it only becomes an issue when it is under compression? So, I found a used crankcase (Complete lower end) online that upon inspection seemed to work just just fine, and installed the new piston, rings and cylinder on to it, put the saw together, tried to pull-start it, and the same thing happens.

So, I scratch my head, pull the spark plug, and tug on the pull-starter, and it pulls easily!

So, I think, maybe I put the piston in backwards? I pulled it apart again, and find that the piston was installed correctly.

I have gone through every thing that I can think of could possibly be the problem: pulled the spark arrestor, pulled the muffler, pulled the carburetor, intake manifold to no avail.

I have pulled everything off of the motor and tried to pull-starter and get the same results; it is to0 hard to pull to get the motor to turn without really holding it down, or locking it in a vice. But, if I pull the spark plug, it spins easily!

In other words, this saw has a totally different motor in it than what came to me, but I am having the same problem!

Any thoughts?

Ddogwood

Please don’t call the bar a bladeThank you