MS201t Problem

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To be clear you had the clutch completely off and the same results?
To be clear, I pulled the bar, chain and clutch. only to have the same result. Hard pull.

As for hydro locking: I pull the plug and there is no excess fuel coming from the spark plug hole, if I turn the saw upside down. As a matter of fact, there is no gas coming out of the hole.

Lone Wolf....I just want to thank you for your continuing interest in helping me to solve this issue. I really appreciate your suggestions and find that you and I are on the same page. This is a head scratcher that I have never come across in the hundreds of chainsaws that I have repaired. I am beginning to think that the MS201T has some design flaw that makes this saw a lemon. I keep reading that it is underpowered to begin with, hence all the modification articles that are prominent on the net.

Of note: Having limited experience with the MS201T, I did notice that of the two saws that I have had apart, the the piston arm seems to float around on the crank quite freely ( a bit more than I would expect). Also (and maybe related to this "looseness") that of the many times that I have pulled the head off this saw to make sure that I have oriented the piston and rings properly, and have re-installed the cylinder head; I have, then, installed the flywheel, and spun the engine just to check the motion of the piston running through its cycle (without the spark plug in) . What I have noticed is that engine rotation is not smooth. That every time that the piston approaches, and passes, top-dead-center, it gets a bit harder to turn, and then "Clunks" past the top of its stroke. There is no compression..the head is open, via no spark plug!

Once the saw is completely re-assembled (and without the spark plug installed), I pull on the pull-starter slowly, to check the motion, or rotation of the engine, and have the same result. That is, as the piston approaches TDC it gets stiffer, and then, "Clunks" past TDC, and then gets easier until the piston, once again, approaches TDC. Put the Spark Plug back in (and the saw has compression), the "Stiffness & Clunk" are exacerbated by X 20 fold! This is the problem. The saw is extremely hard to pull right before the rotation hits TDC until it just passes TDC. The saw pulls easily through the rest of the rotation.

It is like the saw could almost get stuck right at TDC under the right circumstances. But, once the saw is running, the momentum of the engine rotation easily pushes the piston and piston arm past TDC.

Does that make any sense to you? Is this a design flaw?

Ddogwood
 
To be clear, I pulled the bar, chain and clutch. only to have the same result. Hard pull.

As for hydro locking: I pull the plug and there is no excess fuel coming from the spark plug hole, if I turn the saw upside down. As a matter of fact, there is no gas coming out of the hole.

Lone Wolf....I just want to thank you for your continuing interest in helping me to solve this issue. I really appreciate your suggestions and find that you and I are on the same page. This is a head scratcher that I have never come across in the hundreds of chainsaws that I have repaired. I am beginning to think that the MS201T has some design flaw that makes this saw a lemon. I keep reading that it is underpowered to begin with, hence all the modification articles that are prominent on the net.

Of note: Having limited experience with the MS201T, I did notice that of the two saws that I have had apart, the the piston arm seems to float around on the crank quite freely ( a bit more than I would expect). Also (and maybe related to this "looseness") that of the many times that I have pulled the head off this saw to make sure that I have oriented the piston and rings properly, and have re-installed the cylinder head; I have, then, installed the flywheel, and spun the engine just to check the motion of the piston running through its cycle (without the spark plug in) . What I have noticed is that engine rotation is not smooth. That every time that the piston approaches, and passes, top-dead-center, it gets a bit harder to turn, and then "Clunks" past the top of its stroke. There is no compression..the head is open, via no spark plug!

Once the saw is completely re-assembled (and without the spark plug installed), I pull on the pull-starter slowly, to check the motion, or rotation of the engine, and have the same result. That is, as the piston approaches TDC it gets stiffer, and then, "Clunks" past TDC, and then gets easier until the piston, once again, approaches TDC. Put the Spark Plug back in (and the saw has compression), the "Stiffness & Clunk" are exacerbated by X 20 fold! This is the problem. The saw is extremely hard to pull right before the rotation hits TDC until it just passes TDC. The saw pulls easily through the rest of the rotation.

It is like the saw could almost get stuck right at TDC under the right circumstances. But, once the saw is running, the momentum of the engine rotation easily pushes the piston and piston arm past TDC.

Does that make any sense to you? Is this a design flaw?

Ddogwood
Maybe the rod bearing is seized or the cyl is made wrong send me the damn thing and I will get to the bottom of it. You missed something . I wonder if the crank is bent? Whats the history was it dropped out of a tree?
 
Maybe the rod bearing is seized or the cyl is made wrong send me the damn thing and I will get to the bottom of it. You missed something .
But, it did the same thing before I installed the new piston and cylinder and crank case assembly. In other words, different rod bearing and different cylinder. but, same problem.
 
I have an early 201 (rear handle), so I'm following this thread with much interest! Mine is anything but underpowered. It is very strong for a 35cc saw. It has had a MM & a timing advance & has also had the original 13,300RPM limited coil replaced with the newer 14,000RPM version which did nothing for the performance, but made it easier to tune.

I hope you get the problem sorted out. Kudos to you for sticking with it!!
 

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