mtronic issues at elevation

[cascadecrawler]

Ive run into some issues with a V1.0 mtronic stihl 261 (2014 model). Saw has a fresh rebuild, new solenoid (white), upgraded orange fuel filter, fresh air filter and carb kit. Runs great at 500' elevation and is able to perform a reset. Problem is, the saw will run very poorly above 4000' and will not run long enough in choke to perform a reset. Operating at higher elevations the saw will eventually die and not restart until at a lower elevation.

Is this a common problem with V1.0 mtronics?

Do I need to upgrade the coil/brain to the newer version?

throw it away and try to find a regular carb version?

Thanks

 

[singinwoodwackr]

Ive run into some issues with a V1.0 mtronic stihl 261 (2014 model). Saw has a fresh rebuild, new solenoid (white), upgraded orange fuel filter, fresh air filter and carb kit. Runs great at 500' elevation and is able to perform a reset. Problem is, the saw will run very poorly above 4000' and will not run long enough in choke to perform a reset. Operating at higher elevations the saw will eventually die and not restart until at a lower elevation.

Is this a common problem with V1.0 mtronics?

Do I need to upgrade the coil/brain to the newer version?

throw it away and try to find a regular carb version?
Thanks

The tech bulletin I read said black solenoids only for the 261
Scroll to #38
https://www.arboristsite.com/threads/good-stihl-info.329254/page-2

 

[DND 9000]

What is the S/N of the saw? Always remember. THIS white solenoid valve is not a general replacement part for all solenoid valves. Always ask your dealer with the specific S/N of the unit what can be used.

 

[SteveSr]

Ive run into some issues with a V1.0 mtronic stihl 261 (2014 model). Saw has a fresh rebuild, new solenoid (white), upgraded orange fuel filter, fresh air filter and carb kit.

Sounds like the saw is running rich. When you rebuilt the carb did you use an OEM kit? Did you set/check the metering lever height? I am assuming that these carbs still have the metering lever.

 

[cascadecrawler]

The tech bulletin I read said black solenoids only for the 261
Scroll to #38
https://www.arboristsite.com/threads/good-stihl-info.329254/page-2

What is the S/N of the saw? Always remember. THIS white solenoid valve is not a general replacement part for all solenoid valves. Always ask your dealer with the specific S/N of the unit what can be used.

We might be onto something here. I was concerned about this, but read quite a few posts of users not having any problems using the white version on older saws. My concerns faded as it ran SOOO well at lower elevation. On top of that I ordered the parts with my SN via Madsens and they said this was the ticket. Looks like I need to confirm what they said.

Sounds like the saw is running rich. When you rebuilt the carb did you use an OEM kit? Did you set/check the metering lever height? I am assuming that these carbs still have the metering lever.

Plug looks great at elevation when its having issues, definitely not rich. OEM kit, but I did not verify the lever height.

 

[cascadecrawler]

Just talked with Madsens and Donny at Walkers up in BC. Madsens confirmed the white solenoid will work in my saw via the S/N. Donny said he throws a white solenoid in everything and hasnt had an issue. No one has experienced this high elevation issue.

 

[oldbuzzard]

I rebuild lots of Stihl 261Cs and now some 362Cs for some volunteer organizations here in Loveland, CO, elevation 5000’. The older Mtronic saws are just dogs with altitude problems. I h

 

[bwalker]

I very run a 400c from 2000' up to just under 10k' without skipping a beat. I believe my saw has the white solenoid.

 

[singinwoodwackr]

I wonder if it is just the older models.

 

[huskihl]

In my experience, which isn’t really all that much, just what I have noticed coming into my shop. It’s more likely a coil/261c mtronic issue. I’ve had a dozen 261c’s here with goofy running issues that checked out fine on the MDG software. They are very reluctant to change tune. They might eventually do it on their own, but it might take 15 minutes of cutting to get them to straighten out.

 

[cascadecrawler]

In my experience, which isn’t really all that much, just what I have noticed coming into my shop. It’s more likely a coil/261c mtronic issue. I’ve had a dozen 261c’s here with goofy running issues that checked out fine on the MDG software. They are very reluctant to change tune. They might eventually do it on their own, but it might take 15 minutes of cutting to get them to straighten out.

Have you noticed that the problem saws are of a certain vintage? I'm thinking about swapping in a v3.0 coil

 

[singinwoodwackr]

OT , but, has anyone tried any of the aftermarket coils on the non-MT 261s?
couldn‘t fine squat via search.

 

[SteveSr]

OT , but, has anyone tried any of the aftermarket coils on the non-MT 261s?
couldn‘t fine squat via search.

There are none for M-tronic.

 

[oldbuzzard]

In my experience, which isn’t really all that much, just what I have noticed coming into my shop. It’s more likely a coil/261c mtronic issue. I’ve had a dozen 261c’s here with goofy running issues that checked out fine on the MDG software. They are very reluctant to change tune. They might eventually do it on their own, but it might take 15 minutes of cutting to get them to straighten out.

I’m definitely thinking it is a coil problem, simply not leaning enough at high altitude.
Asking for opinions here - these saws all have standard mufflers, maybe muffler mods or Bark Boxes would help?
Also maybe switching to a hotter plug? I’m groping for ideas.

 

[huskihl]

Have you noticed that the problem saws are of a certain vintage? I'm thinking about swapping in a v3.0 coil

Yeah, that’s possible

 

[huskihl]

I’m definitely thinking it is a coil problem, simply not leaning enough at high altitude.
Asking for opinions here - these saws all have standard mufflers, maybe muffler mods or Bark Boxes would help?
Also maybe switching to a hotter plug? I’m groping for ideas.

I’m not certain here, but it seems to be something in the mtronic programming. Or maybe a glitch. Sometimes they don’t adjust as often as what the specs say. They may send a lean or rich signal once, 5, 10? times every second or whatever it is, but they don’t seem to actually adjust the tune for existing conditions that often. I have a 462 that was 4 stroking in the cut for 10 minutes, it then woke up and made adjustments up and down for a few seconds and ran perfectly for 10 minutes. Then went rich for a few seconds, and then tuned itself again to run properly. No air leaks. Saw had 12.5 hours on it so it wasn’t likely a fuel filter or rubber line issue.

I’ve also had a 261 here that acted like it was running very lean for upwards of 10 minutes. When the mtron did finally adjust, it went full rich and flooded the saw instantly to where it took 15 pulls with the throttle held wide open to get it started again. And after that, it seemed to adjust itself and run fine.

@cascadecrawler
That 261 ^ was in fact a v1

 

[singinwoodwackr]

There are none for M-tronic.

Hence the "non-mt" in my question.

 

[SteveSr]

I’m not certain here, but it seems to be something in the mtronic programming. Or maybe a glitch. Sometimes they don’t adjust as often as what the specs say. They may send a lean or rich signal once, 5, 10? times every second or whatever it is, but they don’t seem to actually adjust the tune for existing conditions that often. I have a 462 that was 4 stroking in the cut for 10 minutes, it then woke up and made adjustments up and down for a few seconds and ran perfectly for 10 minutes. Then went rich for a few seconds, and then tuned itself again to run properly. No air leaks. Saw had 12.5 hours on it so it wasn’t likely a fuel filter or rubber line issue.

I’ve also had a 261 here that acted like it was running very lean for upwards of 10 minutes. When the mtron did finally adjust, it went full rich and flooded the saw instantly to where it took 15 pulls with the throttle held wide open to get it started again. And after that, it seemed to adjust itself and run fine.

@cascadecrawler
That 261 ^ was in fact a v1

Remember, you are dealing with a computer and software! Ever see any software that doesn't have bugs/defects? Own a new car this is a high percentage software?

 

[oldbuzzard]

Remember, you are dealing with a computer and software! Ever see any software that doesn't have bugs/defects? Own a new car this is a high percentage software?

Stihl has ad plenty of time to de-bug this stuff.

 

[SteveSr]

Hence the "non-mt" in my question.

Too early in the morning!