MS362c running rich, dies at idle

jovol

jovol

ArboristSite Lurker
Joined
Aug 30, 2017
Messages
15
Location
Appalachia
Hello, I'm seeking some help diagnosing my ms362c. It generally runs ok at full throttle, although recently it has had some moments where power dipped, and one instance where a puff of black smoke shot out the exhaust. The most annoying symptom would be that it doesn't idle well when it's warm. To get it to start again, I generally have to hold the throttle open as I pull start it.

The spark plug, air filter, and fuel filter were replaced. I did the mtronic recalibration yesterday. Spark plug generally gets carboned up within a couple minutes after cleaning the soot off. Muffler is very sooted up. I checked the piston and cylinder through the exhaust port and didn't see obvious scoring. For a compression test, the saw will lower quite slowly when held by the pull cord.

I'm guessing it's a carburetor issue, but I'm not well-versed in this stuff. I guess it could also be weak spark? Not sure!! :baaa:
 
Crispexx

Crispexx

ArboristSite Operative
Joined
Jun 29, 2020
Messages
265
Location
California
Try looking for Parts Number 0000 120 5104. Stihl did make a change to the solenoid at some point after the m tronics came out Depending on when you purchased the saw it might be the older version.
 
jovol

jovol

ArboristSite Lurker
Joined
Aug 30, 2017
Messages
15
Location
Appalachia
Build date on the handle is 05/2017. I bought it used about a year ago.

I'll look into that part. Anyone seen a teardown video/thread of an ms362c carb? Seems to be quite the puzzle getting it out.
 
SteveSr

SteveSr

Addicted to ArboristSite
Joined
Mar 3, 2003
Messages
2,395
Location
Raleigh, NC
Build date on the handle is 05/2017. I bought it used about a year ago.

I'll look into that part. Anyone seen a teardown video/thread of an ms362c carb? Seems to be quite the puzzle getting it out.
I believe that there is an "upgrade" kit that will give you an orange fuel filter and a white solenoid. However a wiring harness check is also a good idea as well as a pressure test on the fuel inlet of the carb to rule out any leaks through the carb.
 
SteveSr

SteveSr

Addicted to ArboristSite
Joined
Mar 3, 2003
Messages
2,395
Location
Raleigh, NC
Thought my older mtronic would just be 90 seconds on cold start then kill it for reset?
Reset procedures vary depending on the specific version of M-tronic that you have . I think that there are 3 versions now. I believe that the version follows the ignition coil part number. One of the M-tronic gurus on here could probably help further.

But also don't forget to check the wiring harness and the rest of the carb. I believe that it has internals subject to wear/degradation just like a non-M-tronic carb. Everyone like to blame the computer first when the real problem might be elsewhere.
 
jovol

jovol

ArboristSite Lurker
Joined
Aug 30, 2017
Messages
15
Location
Appalachia
I had a shop look at it. They confirmed the solenoid is no good. They also quoted me to replace the carburetor, they didn't take it apart but I guess they just assume it needs a rebuild? They wanted $220 for it all so I said no thanks and paid the $30 diagnosis fee.

Part number for the white solenoid valve is 0000 120 5104. The carb is a zama, it has three lines on it: 100357c 1140/04E 711A
Could yall help me ID what rebuild kit for the carb I'd need? Also a US source on the solenoid valve? I already have the orange fuel filter so I wouldn't need that, although if the mtronic repair kit is cheaper than just the valve I could just get the kit. Google turns up UK based dealers with the valve around 20gbp. Haven't found a legit US dealer with an online listing.
 
farmer steve

farmer steve

outstanding in my field, 5150
Joined
Feb 8, 2013
Messages
19,316
Location
Stihl, PA
Go with the white solenoid first. If still not running right then go with the carb rebuild. The reset procedure may be different with the new solenoid. Don't think you will find any online. Just thru a dealer.
 
DND 9000

DND 9000

Addicted to ArboristSite
Joined
Sep 11, 2012
Messages
1,199
Location
Germany
No, the white solenoid valve is not usable for this version. This white valve is not a generall replacement part for the older black valve. Most members here say this, but this is not the case. What can be used depends on the control unit. That`s why you should always talk with your dealer. The diaphragm and gasket kit for your carburetor would be 1140 007 1701.
 
Crispexx

Crispexx

ArboristSite Operative
Joined
Jun 29, 2020
Messages
265
Location
California
No, the white solenoid valve is not usable for this version. This white valve is not a generall replacement part for the older black valve. Most members here say this, but this is not the case. What can be used depends on the control unit. That`s why you should always talk with your dealer. The diaphragm and gasket kit for your carburetor would be 1140 007 1701.

I didn’t know this, like everyone else I thought it was a universal swap/fix for the black solenoid. Do you know any more specifics you’d be willing to share?


Sent from my iPhone using Tapatalk
 
jovol

jovol

ArboristSite Lurker
Joined
Aug 30, 2017
Messages
15
Location
Appalachia
The dealer gave me a list of part numbers to replace including the white solenoid valve.
Are US dealers not allowed to sell this stuff online, whereas UK ones are? Quite frustrating that my dealer says this valve will cost $100 when Online UK dealers sells for 25quid
 
dmb2613

dmb2613

Addicted to ArboristSite
Joined
Dec 25, 2017
Messages
1,849
Location
Virginia
t
The white valve is used on m-tronic v.3 versions. In some cases a white valve can replace a black valve, but it depends on the version and the saw, that`s why I say talk to your dealer.

the white one is used to replace all of them and by the way I am a dealer
 
Top