MS261cm Ignition module

[Joe The Arrow]

Hello everyone, I bought a used ms261cm (Mtronic) last october. I've ran the saw a couple of times and while it's running and cutting pretty well, I can't seem to start it in the "start" position. It keeps flooding. So after it pops in the "start" position (it should typically idle in the "start" position), I keep on pulling to the point of flooding, so I then put in the "run" position, hold the throttle and crank untill it finally unfloods and starts.

To try to fix the flooding problem, here's what have done up to now:
- Changed the spark plug
- Changed the gaskets and diaphragms in the carb
- Changed the solenoid (White)
- Changed the gas filter (Orange)
- Tried to reset the MTronic but it would not since it doesn't idle in the "start" position
- Fresh new gas

Saw still flooding when trying to start it in the "start-triangle" position

My next step was to check the spark and ignition module. So when I pull out the spark plug and ground it to the cylinder to check for spark, I get some spark only when I pull hard/quickly on the crank. In other words, I don't get spark if I do a "relaxed" pull (If that makes sense???).

So here I am, trying to figure out if my ignition coil is due and why is my saw still flooding? Any thoughts?

Cheers everyone

Joe

 

[singinwoodwackr]

Hello everyone, I bought a used ms261cm (Mtronic) last october. I've ran the saw a couple of times and while it's running and cutting pretty well, I can't seem to start it in the "start" position. It keeps flooding. So after it pops in the "start" position (it should typically idle in the "start" position), I keep on pulling to the point of flooding, so I then put in the "run" position, hold the throttle and crank untill it finally unfloods and starts.

To try to fix the flooding problem, here's what have done up to now:
- Changed the spark plug
- Changed the gaskets and diaphragms in the carb
- Changed the solenoid (White)
- Changed the gas filter (Orange)
- Tried to reset the MTronic but it would not since it doesn't idle in the "start" position

So my next step was to check the spark and ignition module. So when I pull out the spark plug and gound it to the cylinder to check for spark, I get some spark only when I pull hard/quickly on the crank. In other words, I don't get spark if I do a "relaxed" pull (If that makes sense???).

So here I am, trying to figure out if my ignition coil is due. Any thoughts?

Cheers everyone

Joe

Return the solinoid…id bet it is defective
It takes a drill on fast speed to crank mtronics enough to get a good spark.

 

[cscltd]

I would pop of the muffler and take a pic of piston and post. As a half baked piston can present itself as flooding.

 

[Joe The Arrow]

Return the solinoid…id bet it is defective
It takes a drill on fast speed to crank mtronics enough to get a good spark.

Hmmmm ... could be, but two bad solenoids back to back? That would certainely be a first be a first ... for me at least!

 

[farmer steve]

Try this from cold. Push lever whole way down to choke,start,leave on choke for a bit, then blip the throttle to run position. From warm just set to run position,start. Not sure why but 261's are fussy starters. Good luck.

 

[Joe The Arrow]

Try this from cold. Push lever whole way down to choke,start,leave on choke for a bit, then blip the throttle to run position. From warm just set to run position,start. Not sure why but 261's are fussy starters. Good luck.

Hi Farmer Steve, well that's my problem, the saw will not run in the "choke/start" position, it will only "pop" then it will flood.

 

[farmer steve]

Hi Farmer Steve, well that's my problem, the saw will not run in the "choke/start" position, it will only "pop" then it will flood.

If you get the pop, what happens if you move to run and then try and start? I reread your post about the spark. On mine it seems like I have to give it hard,fast pulls when starting. It's my only mtronic saw that takes more than 4 pulls to start. (I have 4)

 

[Joe The Arrow]

If you get the pop, what happens if you move to run and then try and start? I reread your post about the spark. On mine it seems like I have to give it hard,fast pulls when starting. It's my only mtronic saw that takes more than 4 pulls to start. (I have 4)

After it pops on the "start" position, I switch to run, I pull and it kinda pops a couple of times and then starts when I'm quick enough to blip the throttle. Takes maybe 4 or 5 pulls...

 

[singinwoodwackr]

What's the compression?
Have you pulled the muffler and looked at the piston?

 

[Joe The Arrow]

What's the compression?
Have you pulled the muffler and looked at the piston?

Piston is clean ... No build up ... no scratches. For the compression, I dunno! Dont have compression tester!!!!

 

[MartDalb]

Could you post some pictures of the carb, intake side etc, (without air filter on).
Make sure we can see it all in there, also the choke/start levers etc.

What year is the saw from?

 

[MartDalb]

Also clear picture of this part.

See my picture.

 

[MartDalb]

My reply here is not meant to be “wise guy attitude”, at all.

Let's try to help you out on this issue.
And on that note - Pictures REALLY help us, when we try to figure out what is going on.

My story on Mtronic.
I sold my own MS261 - a few years back.
(it cut/ran better than any of my 260's, when it ran, let’s be clear)

Early model, mtronic – suddenly didn’t start, non runner after 1,5 year or so - barely used.

Stihl fixed it up - but by then I knew, I was not going to own an Mtronic model.
I spend hours, and hours trying to fix it myself, with help from this lovely site.
No luck, had to give up, and ship it to Stihl headquarters. They fixed it for free btw.

Most folks on this forum knows there are steps to take, when a chainsaw does X, Y or Z.
Start by A, then B and if that doesn't work go C, D back to A and retry etc.

The list is actually rather simple, finding the problem and fixing it might not be, but there aren't that many factors, in the end.

Adding Mtronic, just makes this series of "go to" more or less impossible to follow.
You can't troubleshoot anything, and all data goes into the "control module" - which can read what you had for breakfast 3 days ago, but you can't, as a homeowner, do anything without the data reading tool and software.

I received a full 15 pages of diagnostics when my Mtronic was returned to me – and in the end they changed the ignition coil (control module) and solenoid (was a white – changed to green, (even though Stihl’s own info said it used a white version).

I am not bashing Mtronic, or Stihl.
I use Stihl, all day every day – just not Mtronic, because I can’t fix them myself.

 

[Joe The Arrow]

My reply here is not meant to be “wise guy attitude”, at all.

Let's try to help you out on this issue.
And on that note - Pictures REALLY help us, when we try to figure out what is going on.

My story on Mtronic.
I sold my own MS261 - a few years back.
(it cut/ran better than any of my 260's, when it ran, let’s be clear)

Early model, mtronic – suddenly didn’t start, non runner after 1,5 year or so - barely used.

Stihl fixed it up - but by then I knew, I was not going to own an Mtronic model.
I spend hours, and hours trying to fix it myself, with help from this lovely site.
No luck, had to give up, and ship it to Stihl headquarters. They fixed it for free btw.

Most folks on this forum knows there are steps to take, when a chainsaw does X, Y or Z.
Start by A, then B and if that doesn't work go C, D back to A and retry etc.

The list is actually rather simple, finding the problem and fixing it might not be, but there aren't that many factors, in the end.

Adding Mtronic, just makes this series of "go to" more or less impossible to follow.
You can't troubleshoot anything, and all data goes into the "control module" - which can read what you had for breakfast 3 days ago, but you can't, as a homeowner, do anything without the data reading tool and software.

I received a full 15 pages of diagnostics when my Mtronic was returned to me – and in the end they changed the ignition coil (control module) and solenoid (was a white – changed to green, (even though Stihl’s own info said it used a white version).

I am not bashing Mtronic, or Stihl.
I use Stihl, all day every day – just not Mtronic, because I can’t fix them myself.

Hi MartDalb,

Thanks for the infos. I'm pleasantly surprised how fast you guys respond to my questions. (I'm new to all of this).

Unfortunately I'm out of town for work for 7 days, so I don't have my saw with me. But there are some info I can try and give you. The saw is a 2018.

For the picture, I might not have exactly what you are looking for, but here is one of the random shot while working on it that I have in my phone. Once I get back, I can take more revelant pictures.

I also have an 026 that I've changed the piston and carb gaskets, and man they are so easy to work on. The Mtronic is starting to p... me off!!!!

 

[muddy42]

Could you post some pictures of the carb, intake side etc, (without air filter on).
Make sure we can see it all in there, also the choke/start levers etc.

What year is the saw from?

Agree with this. On my 261 the switch mechanism and choke lever broke, giving similar symptoms.

My 261 starts really easily, but I am equally clueless about how to fix mtronic. I understand if all else fails you can buy parts to return them to being adjustable carbed.

 

[MartDalb]

Agree with this. On my 261 the switch mechanism and choke lever broke, giving similar symptoms.

My 261 starts really easily, but I am equally clueless about how to fix mtronic. I understand if all else fails you can buy parts to return them to being adjustable carbed.

Exactly, we need pictures to make sure nothing is sitting the wrong way, or missing etc.

Throw em up once you are back home , then we can perhaps help you better.
We need pictures where the carb, intake, etc are mounted.

The black "box" on your carb, is the place Stihl places their data cable to read info, and under that, as you see in my picture, is the start identifier. This has to be mounted carefully, and not tightened too hard, same as with the solonoid, which is 1Nm no more no less.

There are Stihl service manuals for all those little electric parts etc.
Also they are very clear about changing the solonoid, not only do they use press fluid, but if you handle the solonoid incorrectly, it may be damaged easily, and they can't be refitted because the sealing may be damaged when pulled out of its "seat".

Great times....

On top of that, for the saw to retune, for the new solonoid, is has to run circles in idle etc.
You may already know this, and it's hard if you can't get the saw to idle....

I have access to all these manuals, but they are in Danish, so not really that helpful for you.

I'd like to know which Mtronic version you have.
Check the Stihl sticker on the chainbrake - on the side, there are numbers which should say what Mtronic version it is - see my picture.

 

[stihltech]

I don't see a pressure and vacuum test listed.
As far as spark, yes, you must spin it quite fast. I would also use a spark tester or a plug with a WIDE gap.
It seems we are running circles around the carburetor. Has a pressure test been done on it? Does the inlet needle leak? Is the lever set correctly? If this was in my shop, there would be a new carburetor on it. Sometimes it IS the cure.
As for where the electronics brain is, it is in the ignition module by the flywheel. It controls the solenoid. The other part on the carburetor sends a signal as to choke shaft position. It is only an on or off switch.
Husqvarna has the computer on the carburetor. Try and buy one of them without a dealer resetting. Not happening.
Sorry if I sound a little tense. Today was T540XP 2 and fight the aftermarket parts day at work.

 

[oldbuzzard]

Hello everyone, I bought a used ms261cm (Mtronic) last october. I've ran the saw a couple of times and while it's running and cutting pretty well, I can't seem to start it in the "start" position. It keeps flooding. So after it pops in the "start" position (it should typically idle in the "start" position), I keep on pulling to the point of flooding, so I then put in the "run" position, hold the throttle and crank untill it finally unfloods and starts.

To try to fix the flooding problem, here's what have done up to now:
- Changed the spark plug
- Changed the gaskets and diaphragms in the carb
- Changed the solenoid (White)
- Changed the gas filter (Orange)
- Tried to reset the MTronic but it would not since it doesn't idle in the "start" position
- Fresh new gas

Saw still flooding when trying to start it in the "start-triangle" position

My next step was to check the spark and ignition module. So when I pull out the spark plug and ground it to the cylinder to check for spark, I get some spark only when I pull hard/quickly on the crank. In other words, I don't get spark if I do a "relaxed" pull (If that makes sense???).

So here I am, trying to figure out if my ignition coil is due and why is my saw still flooding? Any thoughts?

Cheers everyone

Joe

Hello everyone, I bought a used ms261cm (Mtronic) last october. I've ran the saw a couple of times and while it's running and cutting pretty well, I can't seem to start it in the "start" position. It keeps flooding. So after it pops in the "start" position (it should typically idle in the "start" position), I keep on pulling to the point of flooding, so I then put in the "run" position, hold the throttle and crank untill it finally unfloods and starts.

To try to fix the flooding problem, here's what have done up to now:
- Changed the spark plug
- Changed the gaskets and diaphragms in the carb
- Changed the solenoid (White)
- Changed the gas filter (Orange)
- Tried to reset the MTronic but it would not since it doesn't idle in the "start" position
- Fresh new gas

Saw still flooding when trying to start it in the "start-triangle" position

My next step was to check the spark and ignition module. So when I pull out the spark plug and ground it to the cylinder to check for spark, I get some spark only when I pull hard/quickly on the crank. In other words, I don't get spark if I do a "relaxed" pull (If that makes sense???).

So here I am, trying to figure out if my ignition coil is due and why is my saw still flooding? Any thoughts?

Cheers everyone

Joe

It is a characteristic of magnetos that the faster they spin, the better the spark. I work on LOTS of 261Cs, what you describe is normal - you have to pull fast, but Imdont subscribe to having to put a drill motor on them.
I doubt the problem is the coil, they are pretty reliable.
Two bad solenoidsbwould not surprise me, although I have never had it happen personally.

 

[oldbuzzard]

Saw your picture, you have a “white” solenoid, which is good. I have to ask the obvious - in the picture it isn’t plugged in …
I would still be suspicious of the solenoid, perhaps it still got some fine debris in it?
Following the red/black wires from the solenoid they go to the micro switch which tells the Mtronic what position the choke is in. I have heard of these being bad but I have never seen it.
Have you tried just using the saw for a while once you get it running?

 

[Joe The Arrow]

Saw your picture, you have a “white” solenoid, which is good. I have to ask the obvious - in the picture it isn’t plugged in …
I would still be suspicious of the solenoid, perhaps it still got some fine debris in it?
Following the red/black wires from the solenoid they go to the micro switch which tells the Mtronic what position the choke is in. I have heard of these being bad but I have never seen it.
Have you tried just using the saw for a while once you get it running?

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