MS-261 C-M Carb Replacement Question

[Centurian22]

Hello all, brand new to AS, I’ve been searching and reading and researching for a couple months now. I plan to buy an MS-261 C-M with a 20” b/c in about three weeks. I live on 10 acres in middle TN and as of now use my saw fairly infrequently. A friend in Maine owns the 261 CM and has been happy with it thus far.

My first question that I haven’t been able to answer by searching is: can the M-Tronic carb be replaced with a standard carb with adjustment screws? I’d prefer to leave out the “why” but if you must know the topic came up when discussing EMP’s. The idea being to purchase and keep a standard carb on hand in case the M-Tronic takes a dump, or for whatever reason is no longer serviceable.

Next can someone put my mind at ease before I bother my dealer with another question: does the 261 C-M come standard with a rim sprocket setup? It seems to but I haven’t found convincing evidence that this is the case yet. I know the chain is .325” pitch, 0.063” gauge, 20” 81 DL, so assuming it DOES run a rim sprocket would it be the 7 pin?

Lastly in regards to chains: stihl green vs yellow I understand is their low kick back and non-low kick back respectively, all other things being equal is that their RM (micro) vs RS (super chisel) designation? Also can both be sharpened by the same 3/16 file size?

I plan to add a “yellow” chain as my second to the green that comes with the saw, but if there’s a major difference in sharpening or requires equipment I may rethink that plan.

Thanks for any help and for the vast surplus of knowledge already here that’s answered countless questions from my overthinking brain.

 

[brock1994]

Comes standard with 7rim.

I don't believe you can change out the carburetor from mtronic to standard.

Yellow chain all the way don't even bother with the anti kickback the depth gauges are nearly impossible to file.

Lastly I would recommend going with the 18" bar and chain set up. I purchased my 261 standard carb with a 20" and regretted it. The 18" is night and day difference. Just my opinion. Hope this helps at all.

 

[brock1994]

Oh also forgot to say, Welcome to AS!!

 

[boomeradf]

Why not just start with the non-MTronic 261 from the get go?

 

[Centurian22]

Comes standard with 7rim.

I don't believe you can change out the carburetor from mtronic to standard.

Yellow chain all the way don't even bother with the anti kickback the depth gauges are nearly impossible to file.

Lastly I would recommend going with the 18" bar and chain set up. I purchased my 261 standard carb with a 20" and regretted it. The 18" is night and day difference. Just my opinion. Hope this helps at all.

I have been debating ALOT on length of b/c and so much that I read says the 261 C-M handles the 20” .325 all day long with no issues, especially if muffler modded (which is as far as I would go with any modification for now). VERY rarely would I be cutting into anything where the full bar or even close would be buried. I’m not locked in to a choice yet so I’ll keep my ears open to opinions. Thanks for the welcome and the input.

Why not just start with the non-MTronic 261 from the get go?

Because much like a manual vs automatic transmission, as much as I like the idea and concept and control of the manual, it doesn’t overcome the convenience and time savings of the automatic / m-tronic. In a perfect world I would have all the time in the world to maintain and tune all my stuff; unfortunately the reality is I work away from home for a month at a time, and I’m only home for 2 weeks, on a growing farm / homestead with a “need to do” list that’s several years long. I will be getting the M-Tronic, I’m just curious if it could be switched out (which I doubted but my friend things would be possible).

 

[dmb2613]

18 in bar and yellow chain and go cut wood never look back

 

[dmb2613]

and I have not replaced a M-Tronic carb in years they got it sown pat now

 

[Stihldoc]

Wow! This idea is a wonderful way to waste time and money. It won't work unless you change the carburetor, choke rod, ignition module, flywheel, and wiring harness.
The CMZ throttle bodies contain 2 electrical components- the solenoid valve and a diode that senses choke shaft position. Without these components connected to the control module (ignition coil), the saw will spark once and die, if it even sparks at all.
I have an old MS261CMZ prototype that was supposed to be destroyed after testing. Needless to say, that didn't happen and I've been using it without issue for 7 years. It has NEVER had a problem of any kind- even when I was using it in waist-deep water cutting up a tree that fell into a lake. If that wasn't a testament to MTronic dependability, I don't know what is!
20 years from now, all the doubt and controversy about electronically controlled saws will be forgotten. Sure, there's always that one odd guy down the road who still drives his 1967 Buick. He puts up with ****** mileage, poor cold performence, and mediocre dependability because he "doesn't trust" electronic ignition and fuel injected cars. I grew up putting points in my Volkswagen twice a year. I really don't miss this part of the "good old days". My truck has almost 300K on the clock and its still going strong. I don't miss the Tyrannosaurus Rex either!
If you want something that you can fix, get an axe. Otherwise, life, progress, and innovation will pass you by. Just as surely as traffic passes Chas when his old Buick goes tits up.

 

[Be Stihl]

18” bar, yes it’s 7 pin, yellow chain either RM semi or RS full chisle. Muffler mod and it seems to have plenty of power, as well as reliable for me. Welcome aboard!


Sent from my iPhone using Tapatalk

 

[hedge hog]

I bought a 18 and a 20 with my 261 c-m and thought would not use the 20 that much
But all I use is the 20 because of the reach the 18 and even a 16 I’m bent over too much and it kills my back


Sent from my iPhone using Tapatalk

 

[Centurian22]

I bought a 18 and a 20 with my 261 c-m and thought would not use the 20 that much
But all I use is the 20 because of the reach the 18 and even a 16 I’m bent over too much and it kills my back


Sent from my iPhone using Tapatalk

This has been my line of thinking as well. I’m not old yet (even though I feel like it some days), but I know I’m not getting any younger either. I’m not racing the saw or burying it completely into oak or bodark and I’m coming from a Poulan “Pro” (I hate using those phrases together) 42cc 18”, so I’m 99.99999% sure my new 261 even with a 20” bar is going to run like a screaming banshee (especially after a few tanks when it “wakes up” as everyone seems to say) compared to anything that POS4218 ever did.