MS261cm Ignition module

[oldbuzzard]

You may have answered this already but, when cold, have you tried starting it in the Run position first, not putting it down in the Start/choke position?
I don’t buy in to having a compression problem - stuck rings or leaky seals. Just FWIW, I’m retired, I run and fix chainsaws with volunteer groups. I buy dead saws off eBay, repair them, and donate them to the groups or individual volunteers. I’ve done more 261Cs than anything else. I like the Mtronics because I’m in really variable conditions - altitudes, temps. My experience is 261Cs, and 362Cs, can be quirky but sometimes they sort themselves out with continued use as the Mtronic “learns”. My thinking is it has to be something in the Star circuit - bad micro switch on the carb, bad wire on the harness, failure in the coil (control unit), or the “learned” start fuel setting needs to correct itself.
If you are not in a hurry I can send you another control unit to try. I have some I won’t be using. Long story but where I live the older control units won’t lean out enough in high/hot conditions in the summer. In Montreal they should work fine year round.
Scott

 

[MartDalb]

Well, on this picture it has the "old solenoid". I replaced it with a brand new one (Thinking it was the problem). I didn't have the chance to run for a long time. But yes, the saw will start and cut. Pretty well actually. When I replaced the solenoid I had the chance to make make a couple of cuts in 16" dry ash. But that said, it still flooded at startup. When the saw is hot, it starts good. One pull.

@stihltech No vacum test. Not equiped for that. It is my intention to bring it to a stihl dealer to have the mtronic reset since I cant't perform the reset myself. And I will ask him to a vacuum test.

@MartDalb Maybe I'm wrong but in north america the sticker is on the inside of the handle. And for what I seem to understand, Stihl icluded the Mtronic versions from version 2.1. I have no Mtronic version on the sticker. So I suppose it's a 2.0

I am just going to put in stihls own description here, translated as best I can, from Danish....

Note on the Stihl sticker/sign
STIHL M-Tronic- version
1142 967 3301 A – M2.1 2.1
1140 967 3304 B – M3.0 3.0

If there is no such information on the sticker/sign, the M-tronic version is under 2.1.

There are then 2 different ways of calibration of the solonoid.

The old version, if you have that - no M-tronic info = old version below 2.1
Requires the following process.

For a better calibration, first clean up air filter, etc.
Run the saw with several throttles of gas.
Untill warm - atleast 1 minute.
Turn off the saw.

Then, dismount bar and chain.

Put the saw in "start" position
Do not touch the throttle.
Let the saw idle for atleast 90 seconds.
Stop the saw.
The saw is now recalibrated to the new solonoid.

The newer versions requires a little more detailed explanation/process.
I can add it, but only if anyone needs it. - it is in Danish


Now I will add a note, on the solonoid color.
My saw came with a white solonoid, I bought and replaced with a white, and that did not fix my issues.
After it came back from Stihl headquarters, it was replaced with a green solonoid, along a new control unit.
My saw was early version M-tronic from 2014.

 

[MartDalb]

You may have answered this already but, when cold, have you tried starting it in the Run position first, not putting it down in the Start/choke position?
I don’t buy in to having a compression problem - stuck rings or leaky seals. Just FWIW, I’m retired, I run and fix chainsaws with volunteer groups. I buy dead saws off eBay, repair them, and donate them to the groups or individual volunteers. I’ve done more 261Cs than anything else. I like the Mtronics because I’m in really variable conditions - altitudes, temps. My experience is 261Cs, and 362Cs, can be quirky but sometimes they sort themselves out with continued use as the Mtronic “learns”. My thinking is it has to be something in the Star circuit - bad micro switch on the carb, bad wire on the harness, failure in the coil (control unit), or the “learned” start fuel setting needs to correct itself.
If you are not in a hurry I can send you another control unit to try. I have some I won’t be using. Long story but where I live the older control units won’t lean out enough in high/hot conditions in the summer. In Montreal they should work fine year round.
Scott

This is really, really solid help and I wish that was something available in Denmark.
People here are never ever that helpful, or trustful etc.

Simply put awesome @oldbuzzard

 

[Joe The Arrow]

Hello everybody, so as requested, here's a pictutre of the carb and sticker

@oldbuzzard I have not tried to cold start it inb the "run" position. I'm not in a hurry . I think a friend also has a 261cm, I could swap the coil to see if it "fixes" my problem?!?!?!

Any other picture could be of help?

 

[Joe The Arrow]

UPDATE: @oldbuzzard I have tried to cold start de saw in the "run" position. It started succesfully, 4-5 pulls

 

[oldbuzzard]

Ok, just try using it and starting in the Run position. It may (or may not) cure itself over several days of use. It, IMHO, is just a problem in Start mode of being too rich. BTW, I have seen this condition happen numerous times on 261Cs when we are running saws at 7500’ ASL and especially in warmer weather (high/hot). The carb really needs to go leaner. The solution I found is go to the Stihl dealer and buy the latest iteration of the coil/control unit. I don’t remember the whole pn but the last two digits will be 32. If you are operating in the Montreal area I’m surprised you have this problem.

 

[DND 9000]

Go to your dealer with the S/N of the saw and let them look up the right part for you.

 

[oldbuzzard]

Go to your dealer with the S/N of the saw and let them look up the right part for you.

All the 261Cs, at least according to my dealer, supersede to -4732 coils. I am putting those in all the 261Cs that I maintain, no matter how old the saw.

 

[Joe The Arrow]

All the 261Cs, at least according to my dealer, supersede to -4732 coils. I am putting those in all the 261Cs that I maintain, no matter how old the saw.

So here I have my friends Ms261c ... He has the 3.0 mtronic.

Do you think I should try his control unit on my saw

Here are some pics
4701 = MS261c Mtronic 2.0 (or older)
4734 = MS261c Mtronic 3.0

Could it solve something on my saw? Could it make things go bad on his saw after I swap it back in?

 

[oldbuzzard]

I wouldn’t hesitate to put it in. The -4701 is the original pn and has been upgraded at least several times, like a -4716. Interesting - my dealer said there was no such thing as a -4734 coil last year, even though I had already seen one. Just goes to prove that you can’t take the dealers word as gospel.

 

[Joe The Arrow]

I wouldn’t hesitate to put it in. The -4701 is the original pn and has been upgraded at least several times, like a -4716. Interesting - my dealer said there was no such thing as a -4734 coil last year, even though I had already seen one. Just goes to prove that you can’t take the dealers word as gospel.

Hello Scott, tried the 4734 Control Module and didn't change anything. I think my next step would be to try the switch unit as mentioned by @MartDalb in a previous post?

 

[DND 9000]

You can`t go by the number on the part itself. It is no valid part number. You always have to go by the IPL part number. So your dealer is right when he says there is no 4716 or other number, because it is no IPL number. And that is also one more reason why I always say go and ask your dealer insted of messing around by yourself without proper knowledge.

 

[Lightning Performance]

Does the high idol position work on the control lever?

Have you checked that the throttle is infact held open when in the choke position?

 

[Joe The Arrow]

Does the high idol position work on the control lever?

Have you checked that the throttle is infact held open when in the choke position?

When you say high idle, I assume it must be the "triangle/start" position? Mecanically, everything works. The throttle works.

 

[Joe The Arrow]

Hello Scott, tried the 4734 Control Module and didn't change anything. I think my next step would be to try the switch unit as mentioned by @MartDalb in a previous post?

GO IT!!!!

So, I swaped the "switch unit" with my friends saw ... and ... it worked!!!! Started the saw as an Mtronic should be started. 2 pulls and it ran at high idle on the "Start/triangle" position.

 

[Lightning Performance]

When you say high idle, I assume it must be the "triangle/start" position? Mecanically, everything works. The throttle works.

It bumps up the throttle position on most Stihl single control lever saws. Had a 660 once they installed the wrong trigger interlock on the top. No high idol. Choke on three pulls to pop and it would flood. Replaced that operator presence lever then found out they ground down the main control lever. Two stock plastic parts fixed all the hard start issues. Zoomed right up on idol when it starts. Small things break sometimes or get worn. Plastic can be defective or chipped. This was butchered.

 

[oldbuzzard]

You can`t go by the number on the part itself. It is no valid part number. You always have to go by the IPL part number. So your dealer is right when he says there is no 4716 or other number, because it is no IPL number. And that is also one more reason why I always say go and ask your dealer insted of messing around by yourself without proper knowledge.

Yes you are absolutely right about PNs being screwed up. I’m not trying to poo-poo Stihl saws but this is just one of the various things Stihl does that is extremely screwed up. You can buy a control module and it comes with one part number listed on the box, then you open it and the part has a different “part number” on the part. That is crazy. Maybe I’m overly sensitive about this but I spent my working life in the aviation industry and if an aircraft parts manufacturer did that the FAA would shut them down.

 

[oldbuzzard]

GO IT!!!!

So, I swaped the "switch unit" with my friends saw ... and ... it worked!!!! Started the saw as an Mtronic should be started. 2 pulls and it ran at high idle on the "Start/triangle" position.

Glad you got this solved. Question - can you buy just the switch from Stihl?

 

[DND 9000]

You mean the trigger unit. Yes you can buy it. 1141 430 1028

 

[MartDalb]

GO IT!!!!

So, I swaped the "switch unit" with my friends saw ... and ... it worked!!!! Started the saw as an Mtronic should be started. 2 pulls and it ran at high idle on the "Start/triangle" position.

Good to hear.

Get a unit and go cut.

I could technically look up your sn, but for switch unit, it may not be needed.

Glad you found the issue!