How to adjust the idle on the MS261C?

[rustyb]

I didn't look too hard, and the lighting was poor and my eyesight isn't what it used to be. But....I didn't see an idle adjustment screw that is typical of every other carb I've been around. And my idle somehow increased to the point of my chain spinning pretty fast at "idle".

What the heck?

 

[Crispexx]

Is it an M tronic saw? If it is there won’t be any screw holes to do any adjustments on the carb


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[Vintage Engine Repairs]

I didn't see an idle adjustment screw that is typical of every other carb I've been around.

…the joys of technology!

 

[rustyb]

Is it an M tronic saw? If it is there won’t be any screw holes to do any adjustments on the carb


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Yes.

 

[SimonHS]

It's worth resetting it. Do you know which M-Tronic version you have? There is a different procedure for the older and newer versions. Here is a link to some info from Stihl:

https://blog.stihl.co.uk/perform-m-tronic-reset/

 

[sawfan123]

If the linkage is ok, the description you give is a symtom of an air leak.
Minor leaks can be compensated for by the system.
That doesn’t make them any less deadly to the saw.

 

[rustyb]

If the linkage is ok, the description you give is a symtom of an air leak.
Minor leaks can be compensated for by the system.
That doesn’t make them any less deadly to the saw.

That doesn't sound good! I'll check to see if I can see anything obvious.

 

[lone wolf]

That doesn't sound good! I'll check to see if I can see anything obvious.

Hold on , look and see if a clutch spring broke . Do you have a tach?

 

[rustyb]

It's worth resetting it. Do you know which M-Tronic version you have? There is a different procedure for the older and newer versions. Here is a link to some info from Stihl:

https://blog.stihl.co.uk/perform-m-tronic-reset/

Thanks for the link. I'm not sure which version I have. I bought it new in 2016.

 

[rustyb]

Hold on , look and see if a clutch spring broke . Do you have a tach?

Thanks. I do have a tach. How does a tach and clutch spring relate?

 

[lone wolf]

Thanks. I do have a tach. How does a tach and clutch spring relate?

Well if a spring broke the chain will spin at idle . If the tach says the idle is higher than it should be then it could be an air leak or something .Just post the rpm and look at the springs and we can go from there

 

[Crispexx]

Anothobg thing I come across a fair amount is make sure your clutch drum is clean as well, similar idea as a broken clutch spring


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[rustyb]

Ok. I looked for anything obvious. Couldn't see the springs (don't know how to get to them). However, there was some baling twine wrapped around the shaft between the sprocket and washer.

I removed the baling twine, blew out the junk in there, and cold started it with the brake on. Without touching the throttle, I let it idle with the brake on for 60-90 seconds. The tach was reading 3880-3890 rpm.

I blipped the throttle, took the brake off and boom! Chain was no longer spinning at idle. The RPMs were then reading 2810-2820.

Did I just reset it? Or was it the baling twine?

 

[Crispexx]

Ok. I looked for anything obvious. Couldn't see the springs (don't know how to get to them). However, there was some baling twine wrapped around the shaft between the sprocket and washer.

I removed the baling twine, blew out the junk in there, and cold started it with the brake on. Without touching the throttle, I let it idle with the brake on for 60-90 seconds. The tach was reading 3880-3890 rpm.

I blipped the throttle, took the brake off and boom! Chain was no longer spinning at idle. The RPMs were then reading 2810-2820.

Did I just reset it? Or was it the baling twine?

Probably a mix of both. The reset is the same idea as the “did you unplug it and plug it back in?” For the mtronic. If you had a chunk of bailing twine in there you should give it all a good looking over if you haven’t already just to make sure it didn’t take anything out.


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[lone wolf]

Ok. I looked for anything obvious. Couldn't see the springs (don't know how to get to them). However, there was some baling twine wrapped around the shaft between the sprocket and washer.

I removed the baling twine, blew out the junk in there, and cold started it with the brake on. Without touching the throttle, I let it idle with the brake on for 60-90 seconds. The tach was reading 3880-3890 rpm.

I blipped the throttle, took the brake off and boom! Chain was no longer spinning at idle. The RPMs were then reading 2810-2820.

Did I just reset it? Or was it the baling twine?

Well its fixed. I don't see how the twine would increase rpm's.

 

[rustyb]

If you had a chunk of bailing twine in there you should give it all a good looking over if you haven’t already just to make sure it didn’t take anything out.

The twine was just tiny threads that had been wrapped around the shaft. It was not an intact piece of twine. The heat had melted the twine threads somewhat so it was stuck on good.

 

[lone wolf]

The twine was just tiny threads that had been wrapped around the shaft. It was not an intact piece of twine. The heat had melted the twine threads somewhat so it was stuck on good.

That may not affect much, but without a pic IDK.