MS261CM M-Tronic Issues and Many GFY’s

[huskihl]

New carb kit came in today. Report back tomorrow.....

 

[Redfin]

I thought thats what he wrote. Had the dumbs.

 

[RI Chevy]

Your better than that John.

 

[Mastermind]

Burp

 

[Redfin]

Gas? Again?

 

[Mastermind]

Gas? Again?

So?

 

[huskyboy]

New carb kit came in today. Report back tomorrow.....

Have you experimented with other saw carbs and diaphragms? Curious to read your findings.

 

[huskihl]

Have you experimented with other saw carbs and diaphragms? Curious to read your findings.

Yeah, but not to intentionally allow more fuel through a pump diaphragm. The one in the 261 is plastic. For $7, I'll find out if the brown one works better. I'm doubtful, but it can't hurt to try it

 

[Redfin]

So?

What?

 

[00wyk]

Had to gut the stratos on my 241 to stop the off idle bog. Also, it's on it's third carb. I was gonna only buy a solenoid when I noticed the part number on the Walbro the dealer showed me was different. Yeah, it's a Stihl Wtf-1B or some such, but the actual Walbro part number was different stamped on the face of it. SO I went and gave it a try. WOrks well...for now...

OK, found the Walbro part #s. Now these might be different from over the pond:

The saw had a WTF-408 on it, the new part is WTF-321. Both say wtf-1b on them...

I replaced it for farm use with the Echo 390ESX, tho:

 

[Stump Shot]

Yeah, but not to intentionally allow more fuel through a pump diaphragm. The one in the 261 is plastic. For $7, I'll find out if the brown one works better. I'm doubtful, but it can't hurt to try it

This and if the saw has some time on it already it's not unthinkable that the metering diaphragm isn't flexible enough either.
Tillotson for example recommends for high performance applications a gasket and diaphragm set after one years use and a complete rebuild after the second year to keep the carburetor performing properly.

 

[00wyk]

This and if the saw has some time on it already it's not unthinkable that the metering diaphragm isn't flexible enough either.
Tillotson for example recommends for high performance applications a gasket and diaphragm set after one years use and a complete rebuild after the second year to keep the carburetor performing properly.

True, and it wouldn't hurt. But bear in mind when they say 'high performance' that Tillotson do a lot of stff like this:

 

[malk315]

Changed nothing except mix to VP Racing 92 octane and Saber at 42:1. Saw felt like it would do same, but it compensated.

Sorry for long video, I wanted it to happen again, but it didn’t.

Saw still shuddered after coming out of the cut.

The dieseling sound coming out of the long cut sounds like a "low needle is lean issue". My 385 is like that sometimes on a long, hard cut but I don't worry and like the zippy transition I have with low where its at.

Perhaps mtronic reacts with low needle but the instant transition from WOT on a high temp load to idle the MT reacts but it takes time for low to deliver the needed fuel to not diesel sound for a few seconds

IMO not a problem but annoying.

This all assume the MT manages the low needle in a sane way

Really wish you could plug in a wire to the MT and have a computer display and record all key MT sensors and and plot of needle movement so you can know what needles are doing. Any way to extend the shafts of the servos or stepper motors that turn the needles (I would be way off) to put a dial indicator on so you could watch the needles rotate? Probably a pipe dream but a sacrificial mt carb u could watch the needles turn would be a start.

Just thinking out loud here.


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[malk315]

And as I further catch up on the thread the problem is solved with squish. Awesome.

Also some good derails on shots of 2 cycle oil etc. The movie "over the top" with sly Stallone one of the competitors wacks down a quart of motor oil to psych himself up and mess with his opppnent... LOL.

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[wcorey]

AND I'll bring my saws so I can cut some wood along the way. Leave your saws on the shelves so they don't get dirty.

This coming from someone who won’t cut in the rain for fear his saws will get wet.
Oh, the irony... Lol.

 

[RI Chevy]

Yes sir Bill. Nothing good happens from cutting in the rain. I don't need the wood that bad. AND I use my saws, I don't beat on them.
No sweat.

 

[Stump Shot]

True, and it wouldn't hurt. But bear in mind when they say 'high performance' that Tillotson do a lot of stff like this:

They all operate the exact same way and have the same influences happen to them over time and use as far as the diaphragms are concerned. A stretched pump, warped inlet flapper, leaking seat or stiffened metering diaphragm will make the performance suffer all the same.
It's the high performance engine that will notice it before a lower performing engine will.

 

[huskihl]

This and if the saw has some time on it already it's not unthinkable that the metering diaphragm isn't flexible enough either.
Tillotson for example recommends for high performance applications a gasket and diaphragm set after one years use and a complete rebuild after the second year to keep the carburetor performing properly.

This one was NIB when I got it

 

[malk315]

This coming from someone who won’t cut in the rain for fear his saws will get wet.
Oh, the irony... Lol.

 

[malk315]

And as I further catch up on the thread the problem is solved with squish. Awesome.

Also some good derails on shots of 2 cycle oil etc. The movie "over the top" with sly Stallone one of the competitors wacks down a quart of motor oil to psych himself up and mess with his opppnent... LOL.

Sent from my XT1585 using Tapatalk

Here's the motor oil drinking:

Maybe wack down a mug of Klotz benol to get the joints lubed up? LOL.