Stihl MS261C, MS261 What is the Difference?

[Ribsy]

Does anyone know what is different about these two saws and also the C-M designation?

[GAB]

According to the Stihl Power Tools and Accessories catalog on page 132:
C Features
B = QCA (Quick Chain Adjuster)
E = Easy2Start (TM)
M = STIHL M-Tronic (TM)
Q = STIHL Quickstop Plus- an additional chain braking feature
R = Wrap handle
T = Top handle (on the nameplate)
VW = STIHL Artic (TM)

Hope that answers your question.
Gerald

[4x4American]

The C means it has a computer controlled carb.  There are no tuning pegs on it, it's all done by way of a computey box.  All of the new computer aged saws are going to this.

(Eventually, the saws are going to have gps units and internet connectivity, and the epa will be able to shut down your saw if there's fire danger in the area you're in.)

[Ribsy]

Thanks for the replies! I am fine with the new technology...if it works reliably. Somehow, I just don't believe it will.

I recently had 6 saws and a winch stolen out of my shop. I lost a Husky 365 24", Stihl 036 attached to a Lewis Winch, Stihl 026 16", Stihl 192T 12", a Craftsman 20" and an Echo 4400 18". The last two were given to me by my father.

$3,000 worth turned into $1,000 after the insurance turned its screws. Your screwed if you don't have insurance and you're screwed if you do!

So, I looked at all the saws out there, Husky, Jonsard, Dolmar, Stihl, Echo and finally decided to go with the shop that I felt would give me the best service, and they sell Stihl. I wanted to get a professional unit this time, I wanted it to be new and I wanted a medium sized unit as a compromise. My use is for firewood and I have mill. Also, I run a small property maintenance and landscape company.

So, I bought what they sold me. A Stihl MS 261C, 18" bar. I'm in it for almost $700, retail plus tax, plus an extra chain. I figure I can apply the other $300 to a used 70cc saw when the opportunty presents. Meantime, I have spent most of the remainder on some security measures around and inside of my shop.

The new saw runs great and has real good power. But what saws don't when they are brand new. After I had picked up the saw, I realized there were no carb adjustment holes in the outer shell and I opened it up and found an electronic gizmo stradled over where the srews are usually located. Asked the guy at the shop and he was surprised and seemed puzzled.

Call me old school, but I just don't trust someting that I don't understand and probably won't be able to figure out. I can't imagine ever buying a car that drives itself, or driving next to one. At some point the chip is going to go bad and all hell breaks loose or in the case of the saw, stops running. That would not be good.

Any way, thanks for the responses and happy new year to all! Any comments will be appreciated even if someone wants to tell me I made a bad choice or if Jeff wants to reloce this post to the Having A Challenging Day board. 😄😄😄

[JohnG28]

The original 261 had a standard carb with the computer carb only on the CM version. Since then, all 261s have been changed to the computer carb, and I believe that's when they were designated 261C. As for your worries, I have heard nothing but good things about the saw you bought. People seem to like them a lot. And your car's engine is controlled by a little computer chip too and we never give them a second thought. So, enjoy the saw and run it like you stole it!  ;D

[Ribsy]

Ha! Then that I will sir. Thanks for your response! 😅

[missedbass]

Have heard all good reviews on the 261c, good luck with your purchase. Too bad about the theft of your saws. Hope they get the thief.

[SawTroll]

Have heard all good reviews on the 261c, good luck with your purchase. Too bad about the theft of your saws. Hope they get the thief.

The M-thronic version often is called 261C, but the correct designation really is 261C-M.

[missedbass]

Yes that's correct. At the dealer I did see one that said 261c, maybe that was the early edition? I thought it would have said 261cm on it.

[joe_indi]

I think just a C would mean Catalytic Convertor verson or Comfort version (easy start, purger etc)
C-M, (I am just guessing here) probably one of the above with Mtronic.

I stand corrected.  :  This is it!http://www.stihlusa.com/products/chain-saws/professional-saws/ms261cm/

And Mtronic should read as M-Tronic

[Ribsy]

It is a little confusing. All I know is that mine has a C only and that the carburetor does not appear to be adjustable.

[missedbass]

like ST says, that is the m-tronic.

[SawTroll]

The "C" means it has one or more of the features listed in reply #1 (except R or VW, that are used without a "C" in front of them).

[4x4American]

You made a fine choice for a saw.  Shocked the dealer didn't know anything about the computer controlled carb.  I had a friend who bought a stihl 441c, and it wasn't working right since he got it, he brought it back in and the dealer changed the computer on it or plugged his computer in or something and he's loved it ever since.  I'm with you on the whole trusting it part.  What if it goes bad and leans the saw out and then seizes it.  On the other hand, I get nervous trying to tune a saw with a limited coil on it, because I can't use my tachometer and have to tune it in the wood. 

[Bilge Rat]

Good mid sized saw.
Read your manual on running it. The M-tronic learns as you cut, run it in bigger wood to put a load on it and don't let it sit at idle for long periods.
It runs stronger after 5 to 10 tanks of fuel.

Get some non ethanol gas, all your saws will run better on it.
Another thing, don't believe the EPA. Run your saws at 40 to 1.  Your saws bearings will be happier and that 261 will run great for years.

If you open the muffler up a little with a few fish gills on the left side that saw will make even more power.  The M- tronic will adjust for it.

[4x4American]

good advice ^^

[lamimartin]

Good mid sized saw.
Read your manual on running it. The M-tronic learns as you cut, run it in bigger wood to put a load on it and don't let it sit at idle for long periods.
It runs stronger after 5 to 10 tanks of fuel.

Get some non ethanol gas, all your saws will run better on it.
Another thing, don't believe the EPA. Run your saws at 40 to 1.  Your saws bearings will be happier and that 261 will run great for years.

If you open the muffler up a little with a few fish gills on the left side that saw will make even more power.  The M- tronic will adjust for it.

I own a classic MS261 for general use and a MS660 Magnum to fell large trees, cut oversize logs and as main saw for my portable Logosol M8 sawmill.  I appreciate the much lighter MS261 which is probably the ideal weight, handling and power compromise for general work. The MS261 main limitation I discovered over version 261c or 261c-M is the fact chain oil flow is NOT adjustable on an old MS261, at least on mine. Considering this fact, I do not use it on a chain bar longer than 20 in. In fact I use the original 16" bar most of the time to keep the weight, easy handling and balance I like most. In my case, the MS 660 can handle any bar size I use up to 36 in, thanks to the adjustable bar oil pump and extra power.  Both are old fashion manually adjustable carbs, which use more fuel and are less adaptable to variable weather and load conditions than the M-Tronic versions.

I'm a bit surprised to read a recommandation to use an fuel oil ratio of 40:1 instead of the Stihl recommended standard which is 50:1. I am certainly concerned about protecting the bearings, but I think this can lead to change prematurely dirty spark plugs, not to mention excessive smoke. Is this a common practice among professionals ? I certalnly want to keep both my chainsaws in good shape for a long time and I am quite careful about preventive maintenance, but 40:1 ??? Does is makes such a great difference without much effect on the spark plugs, ability to start and run without excessive smoke ?  I would like more opinions and facts on that point.

As for fuel, I NEVER use anything but super unleaded WITHOUT ethanol... I fully agree with this extremely important recommendation for any 2 strokes small engine.

Best regards and best wishes for 2015 !

Martin

[Bilge Rat]

No excessive smoke. It will have a puff of smoke when you first rev it up but nothing much afterwards.
New oils are much different than even 10 years ago.
Older caster based oils lubed real good and still do but carbon up the motor without regular cleaning. Castor is still one of the best for long duration hi rev racing applications.

The newer ester based oils are high in detergents, low sulfur, and low smoke. For our uses these oils work and are clean.

The 50:1 is more for EPA compliance, it will work but if anything is not right with the saw it is not enough oil to protect it.

We run everything at 40:1, weedeaters, stock saws, edgers, blowers etc with no plug or carbon issues.

I run 32:1 in a ported 361. Puff of smoke at start then clean. Still running the same plug that the porter put in it, that was 15 to 20 tanks ago. Piston is clean still.
I have not cleaned/ replaced a plug in anything in over 4 years.

We run Belray H1R, Maxima K2 or Motal 800. all are great oils.
The Stihl orange bottle at 40:1 will slowly crud up the muffler screen over time. Clean it 2X a year and go.
The silver Stihl is cleaner at 40:1.

When you pull down a motor run at 40:1 you see an oil film on the parts, that is protection.

I tune my carbs at any major temp or weather change as needed. Listen and keep the motors running right.

One weedeater/brushcutter is 20 years old and still strong running. It is used on the farm.
50:1 VS 40:1 is only .6 oz per gall. Or 9/10ths VS 1 gall of gas.

If you run 50:1 be sure you measure the oil AND gas carefully.

I own  024, 026, 036, 039, 261, and 361 all carbed chainsaws some since new and have not fried one yet.

[WUDPIRAT]

+1 on the 40:1 mix.  Oil is cheaper than metal.
My first outboard ran 16:1, and I'm leary of anything leaner.

For you old timers, it was an Elto Ace, 1.8 hp, exposed flywheel that you wraped the pull cord around, float carb with a brass pin you depressed to prime, rotate the whole engine for reverse. had a lever that controled the speed ,advanced the spark.
It was a real two smoke, running down wind was an adventure.
SAE 30w oil. 8 oz to the gal.
:new_year:

[lamimartin]

Based on your comments, I will certainly try the 40:1 mix, especially on my MS660 that will be dedicated to my Logosol M8 portable sawmill next year. I've got to prepare enough lumber to build a 24x32 feet garage with 12' high walls. I think it is probably one of the toughest job a chainsaw can do. I fully agree that "Oil is cheaper than metal", as long as it does the job without its own side effects on obnoxious smoke and excessive residue buildup on spark plug and rings. I will see how it works on my other 2 strokes engine too, except maybe on my outboard, because excessive smoke and oil residue on a lake is a much greater inconvenient than on a chainsaw running in the middle of my maple bush.

This issue about emission control is nothing new: I also own an 1983 Evinrude 8HP outboard that was so called designed for 100:1 oil mix... Evinrude later issued a white paper to all service outlets and clients recommending to switch 50:1 mix instead, because they did not last on 100:1. Mine (a long foot sailboat version) remains in top shape, more than 30 years later...on 50:1 mix. 

I also own a 1980 Honda CM400 motorcycle that runs fine mainly because I only use ethanol free fuel and regular oil changes.  Maintenance and proper fuel is key for machines that work properly and last.  Just any outboard or chainsaw repairmain tell me fuel with ethanol is by far the most common cause of carbs problems, both 2 and 4 strokes. Corrosive effect of ethanol on seals and rubber, rapid degradation from moisture and gum formation is a plague on carbs. The latest models are apparently much worst because of the smaller ports and very thin tolerances designed to save on fuel and reduce emissions.

30 years ago, a tank of gas was stable on its own for a year, until next season. Now, without fuel stabilizer addition, gum buildup will start to occur in only a couple of months. Unless we can afford a drum of aviation fuel, we must add fuel stabilizer, drain carbs and be very careful on engines that are not being used for long periods.  Gasolinel is much cheaper quality than it used to be.   How long are we going to be able to maintain good quality tools with small engines in good shape ? In some cases, synthetic oil helps, but overall, this is getting quite challenging.

Martin

[Ribsy]

Good mid sized saw.
Read your manual on running it. The M-tronic learns as you cut, run it in bigger wood to put a load on it and don't let it sit at idle for long periods.
It runs stronger after 5 to 10 tanks of fuel.

Get some non ethanol gas, all your saws will run better on it.
Another thing, don't believe the EPA. Run your saws at 40 to 1.  Your saws bearings will be happier and that 261 will run great for years.

If you open the muffler up a little with a few fish gills on the left side that saw will make even more power.  The M- tronic will adjust for it.

I want to thank everyone for all of the excellent replies. Interestingly, when I had picked up my new saw, I didn't get the manual with the tool kit. It had been set aside and no one thought about it. When I got home I just downloaded a manual from the Stihl website. The MS 261, 261C manual. No mention whatsoever of the M-tronic. That why I was so confused, considering I had no carb adjustments. Several days later and after I initiated this post, I was able to claim the manual from the shop and sure enough it is the MS 261 C-M. I hope Stihl will do something in the future to reduce such confusion...

A couple of questions that this thread has lead me to:

1) 40:1 is 8 oz to 2.5 gallons, right?

2) What is the proper process to open up the muffler with a few fish gills on the left side? This is new to me.

Thanks again everyone!

[Warped]

+1 on the 40:1 mix.  Oil is cheaper than metal.
My first outboard ran 16:1, and I'm leary of anything leaner.

For you old timers, it was an Elto Ace, 1.8 hp, exposed flywheel that you wraped the pull cord around, float carb with a brass pin you depressed to prime, rotate the whole engine for reverse. had a lever that controled the speed ,advanced the spark.
It was a real two smoke, running down wind was an adventure.
SAE 30w oil. 8 oz to the gal.
:new_year:

My '58 Fleetwin calls for 30 wt.,  now it needs coils and it's first fuel pump.......and I do mean its first. The two line aint lookin so hawt :laugh:

[Warped]

Good mid sized saw.
Read your manual on running it. The M-tronic learns as you cut, run it in bigger wood to put a load on it and don't let it sit at idle for long periods.
It runs stronger after 5 to 10 tanks of fuel.

Get some non ethanol gas, all your saws will run better on it.
Another thing, don't believe the EPA. Run your saws at 40 to 1.  Your saws bearings will be happier and that 261 will run great for years.

If you open the muffler up a little with a few fish gills on the left side that saw will make even more power.  The M- tronic will adjust for it.

I want to thank everyone for all of the excellent replies. Interestingly, when I had picked up my new saw, I didn't get the manual with the tool kit. It had been set aside and no one thought about it. When I got home I just downloaded a manual from the Stihl website. The MS 261, 261C manual. No mention whatsoever of the M-tronic. That why I was so confused, considering I had no carb adjustments. Several days later and after I initiated this post, I was able to claim the manual from the shop and sure enough it is the MS 261 C-M. I hope Stihl will do something in the future to reduce such confusion...

A couple of questions that this thread has lead me to:

1) 40:1 is 8 oz to 2.5 gallons, right?

2) What is the proper process to open up the muffler with a few fish gills on the left side? This is new to me.

Thanks again everyone!

2.5 X 128/40=
2.5 x 128=320/40=8 oz.

128 oz. per gallon
     
Just remember 3.2 oz. of oil per gallon of gas   128/40=3.2
I just took an old dry gas bottle and cut the bottom off and marked it at 3.2 ounces.  When done, put the cap back on and no mess.

[JohnG28]

If measuring for 40:1, use the recommended oil for 50:1 and then use 0.8 gallons instead of full gallons. This will give you 40:1.   ;)

[Bilge Rat]

On the muffler mod question
You can look on some of the other forums and find some good pics/info on just how to do it,  arboristsite has some good threads on this.
One thing is to remove the muffler from the saw and after doing any work to it wash all the metal filings out with brake cleaner before putting it back on.

The saw will pull any trash left in the muffler back into the cylinder causing ugly damage.

Run/breakin the saw for a while before doing anything to it. Any warranty issue will show itself.  Your dealer may not like you modifying muffler if there is any issue. After the saw has proven itself and you have time for research you can do a muffler mod.  It will give you a little more power and it allows the saw to run cooler.

See you are in north Ga. Pretty area and good wood.
Enjoy the saw, it is a good one.