Stihl 661 mtronic wont idle

[DND 9000]

Don`t let it run anymore like this. There is a risk to seriously damage the engine. If you don`t have the proper pressure and vaccum tester with adapters, take it to the dealer. Often the air leaks are on the sealing rings of the cranckshaft, but there are other possibilities too.

 

[Jza]

Don`t let it run anymore like this. There is a risk to seriously damage the engine. If you don`t have the proper pressure and vaccum tester with adapters, take it to the dealer. Often the air leaks are on the sealing rings of the cranckshaft, but there are other possibilities too.

I havnt been running it, trying to get it running lol. Yeah I'm thinking I will have bite the bullet if I can't figure it out

 

[singinwoodwackr]

Bit if an update to the update... think it's an airleak . What happens now is the chain spins at idle at a high rpm . If I spray lots of break clean around the cylinder gasket the saw will idle and eventually die .

I've taken the cylinder off and saw liquid between the gasket and clyinder . cleaned the surfaces and used loctite 518 for sealer . Same results , saw will idle really high rpm .

My next guess would be to check the surfaces are true and not warped .

I don't have the tools to check for air leaks so a can of break clean it is .

If all else fails I'll take it to the dealer

Same issue with a 261 of late. Did vac and press tests…passed.
so, must be carb so swapped it out. Saw idles fine now but it will not go through reset cycle. To start…choke, them hold trigger and pull. After that it starts and runs normally.
weird…

 

[Jza]

Same issue with a 261 of late. Did vac and press tests…passed.
so, must be carb so swapped it out. Saw idles fine now but it will not go through reset cycle. To start…choke, them hold trigger and pull. After that it starts and runs normally.
weird…

I feel your pain ! This saw has been a pain in the ass lol

 

[singinwoodwackr]

Crazy...cuz the 2 661s I repaired with new solenoids are back on the job. But...they got white ones that are no longer available from my dealer. I may call around to others and see if they have any left overs. My gal can only order green now.

 

[Jza]

Crazy...cuz the 2 661s I repaired with new solenoids are back on the job. But...they got white ones that are no longer available from my dealer. I may call around to others and see if they have any left overs. My gal can only order green now.

That's what I got told too.. I have a 660 thats an absolute monster , I was hoping to retire it and upgrade to the 661 with better a.v

 

[Outback1]

Same issue with a 261 of late. Did vac and press tests…passed.
so, must be carb so swapped it out. Saw idles fine now but it will not go through reset cycle. To start…choke, them hold trigger and pull. After that it starts and runs normally.
weird…

Did you check the plastic piece on the flywheel side? The O’ring on that piece goes bad along with the seal or the plastic itself warps causing not to seal properly.

 

[rogue60]

I went through this solenoid crap on two 661 a while back.
Looking on my Stihl dealers computer at the parts diagram the black solenoid is no longer available and the green one is for older saws with 1st gen coil saws only. White solenoid is for the later coiled saws only.
I ended up putting the green one in the older saw and a white one in the later saw this got them both running as should again... well until a solenoid craps itself again lol
I've said it before I hope Stihl have a stockpile of solenoids stashed away somewhere to last into the unforeseeable future, or there will be a lot of 661's sitting on shelves unusable in a decade or two.

 

[singinwoodwackr]

Did you check the plastic piece on the flywheel side? The O’ring on that piece goes bad along with the seal or the plastic itself warps causing not to seal properly.

not familiar with that. Part #? All I see is the seal

 

[singinwoodwackr]

That's what I got told too.. I have a 660 thats an absolute monster , I was hoping to retire it and upgrade to the 661 with better a.v

I have a first gen 661 and have never had any issues

 

[Jza]

I went through this solenoid crap on two 661 a while back.
Looking on my Stihl dealers computer at the parts diagram the black solenoid is no longer available and the green one is for older saws with 1st gen coil saws only. White solenoid is for the later coiled saws only.
I ended up putting the green one in the older saw and a white one in the later saw this got them both running as should again... well until a solenoid craps itself again lol
I've said it before I hope Stihl have a stockpile of solenoids stashed away somewhere to last into the unforeseeable future, or there will be a lot of 661's sitting on shelves unusable in a decade or two.

My dealer seems to think the white one in an outdated solenoid and the green one is the current one . I can only go off what he says but its very conflicting to what everyone else says on this forum .

I don't really care what one I use as long as it works lol

 

[singinwoodwackr]

My dealer seems to think the white one in an outdated solenoid and the green one is the current one . I can only go off what he says but its very conflicting to what everyone else says on this forum .

I don't really care what one I use as long as it works lol

Same here. Just spent an hr or so swapping solenoids, trigger units and another carb on this 261. Played with 2 black, 1 white and a green. Each one worked for reset mode but the saw wouldn't run after that. Idled for a while...wot kills it. Odd because yesterday I couldn't get it to reset but got it to run fine by choke it, then start by holding the trigger and pull start. Then everything worked as normal other than not going into reset. This with an old black sol. Today I wanted to try a green to see if it would reset normally...worked. but, wouldn't run, lol.
I think it is cursed.

 

[Jza]

Same here. Just spent an hr or so swapping solenoids, trigger units and another carb on this 261. Played with 2 black, 1 white and a green. Each one worked for reset mode but the saw wouldn't run after that. Idled for a while...wot kills it. Odd because yesterday I couldn't get it to reset but got it to run fine by choke it, then start by holding the trigger and pull start. Then everything worked as normal other than not going into reset. This with an old black sol. Today I wanted to try a green to see if it would reset normally...worked. but, wouldn't run, lol.
I think it is cursed.

Feel your pain ! No air leaks ?

 

[singinwoodwackr]

Nope ,at least not the case...vac and pressure good. But, the fast idle acted link a leak so swapped carbs...figured carb leak. That stopped the fast idle and it ran normally but wouldn't go into reset mode. (Black sol)
Thinking a nice new green would fix the rest. Goes into reset, no problem but now won't keep running
I tested the initial carb...passed, sigh...

Dealer owes me a favor so will have them hook it up next week.

 

[stihltech]

And sometimes it is the carburetor.
I have a chart that shows what fits what. It may even be on here someplace. It is still a chainsaw. All the same rules apply.

 

[singinwoodwackr]

And sometimes it is the carburetor.
I have a chart that shows what fits what. It may even be on here someplace. It is still a chainsaw. All the same rules apply.

Gonna try another carb on mine but have to replace a broken throttle shaft first.

 

[Jza]

And sometimes it is the carburetor.
I have a chart that shows what fits what. It may even be on here someplace. It is still a chainsaw. All the same rules apply.

Hey any chance if you find that chart you could post it ?

 

[stihltech]

Going to work today. I will try to remember to grab it.

 

[stihltech]

M-Tronic Solenoid valve updates for Professional Chainsaws​

1/4/2023

---

Customer Complaint​

Engine dies at idle or is difficult to restart when hot

Average Time of Failure​

Medium to High runtime

Initial Checks​

• Winter / Summer shutter present and in the correct position?
• Fuel in fuel tank?
• Winter blend fuel during hot weather in the Spring?
• SDS / MDG Solenoid Valve leakage test.

Potential Cause​

Black solenoid valve worn and not sealing when closed.

Action​

Replace M-Tronic Solenoid Valve, Calibrate the Unit.

Replacement / Update information​

MS 201 TC-M <186967963​

Replace black solenoid valve with green solenoid valve (0000-120-5111)
Install new orange mesh fuel filter (0000-350-3522)
Units above the serial break are M-Tronic 3.0 and will be equipped with a white solenoid valve.

MS 261 C-M <522260407​

Replace black solenoid valve with green solenoid valve (0000-120-5111)
Install new orange mesh fuel filter (0000-350-3518)
Units above the serial break are M-Tronic 3.0 and will be equipped with a white solenoid valve.

MS 362 C-M <183609631​

Replace black solenoid valve with green solenoid valve (0000-120-5111)
Install new orange mesh fuel filter (0000-350-3518)
Units above the serial break are M-Tronic 3.0 and will be equipped with a white solenoid valve.

MS 661 C-M <184316256​

Replace black solenoid valve with green solenoid valve (0000-120-5111)
Install new orange mesh fuel filter (0000-350-3518)
Units above the serial break are M-Tronic 3.0 and will be equipped with a white solenoid valve.

Production Improvement​

Production change to White (wear resistant) solenoid valve and M-Tronic 3.0 software in production above serial number:

• MS 201TC-M: 186967963
• MS 261C-M: 522260407
• MS 362C-M: 183609631
• MS 462C-M: Since start of production
• MS 661C-M: 184316256

Part Number(s)​

Original black solenoid (0000-120-5110) can always be replaced with the new green solenoid (0000-120-5111).
In the rare case of a white solenoid (0000-120-5104) failure, please replace it with another white solenoid.
Illustrated parts lists have been updated to reflect these changes.
Black Solenoid (0000-120-5110) is discontinued.

 

[Jza]

M-Tronic Solenoid valve updates for Professional Chainsaws​

1/4/2023

---

View attachment 1104635

Customer Complaint​

Engine dies at idle or is difficult to restart when hot

Average Time of Failure​

Medium to High runtime

Initial Checks​

• Winter / Summer shutter present and in the correct position?
• Fuel in fuel tank?
• Winter blend fuel during hot weather in the Spring?
• SDS / MDG Solenoid Valve leakage test.

Potential Cause​

Black solenoid valve worn and not sealing when closed.

Action​

Replace M-Tronic Solenoid Valve, Calibrate the Unit.

Replacement / Update information​

MS 201 TC-M <186967963​

Replace black solenoid valve with green solenoid valve (0000-120-5111)
Install new orange mesh fuel filter (0000-350-3522)
Units above the serial break are M-Tronic 3.0 and will be equipped with a white solenoid valve.

MS 261 C-M <522260407​

Replace black solenoid valve with green solenoid valve (0000-120-5111)
Install new orange mesh fuel filter (0000-350-3518)
Units above the serial break are M-Tronic 3.0 and will be equipped with a white solenoid valve.

MS 362 C-M <183609631​

Replace black solenoid valve with green solenoid valve (0000-120-5111)
Install new orange mesh fuel filter (0000-350-3518)
Units above the serial break are M-Tronic 3.0 and will be equipped with a white solenoid valve.

MS 661 C-M <184316256​

Replace black solenoid valve with green solenoid valve (0000-120-5111)
Install new orange mesh fuel filter (0000-350-3518)
Units above the serial break are M-Tronic 3.0 and will be equipped with a white solenoid valve.

Production Improvement​

Production change to White (wear resistant) solenoid valve and M-Tronic 3.0 software in production above serial number:

• MS 201TC-M: 186967963
• MS 261C-M: 522260407
• MS 362C-M: 183609631
• MS 462C-M: Since start of production
• MS 661C-M: 184316256

Part Number(s)​

Original black solenoid (0000-120-5110) can always be replaced with the new green solenoid (0000-120-5111).
In the rare case of a white solenoid (0000-120-5104) failure, please replace it with another white solenoid.
Illustrated parts lists have been updated to reflect these changes.
Black Solenoid (0000-120-5110) is discontinued.

Thanks much appreciated!