MS661 -- No Spark

[toadman]

Is that the number on the coil itself, or the box?
The two don't line up according to my dealer & the Emessage I sent Stihl.... the 4704's they had in stock here said 4702A

 

[PogoInTheWoods]

Correct. Sorta... 1144 400 4704 is the part number on the ECM itself and translates to the 4702A Gen 3 software. (1144 400 4703 modules actually have 4702 inscribed on the module..., not to be confused with a 4702A module, but still a Gen3 coil))

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[PogoInTheWoods]

And as a possible point of interest on the green solenoids, I happened to glance at the little instruction sheet included in the box with a black solenoid I was installing in a v1.1 saw yesterday and noticed the green solenoid part number included with the black and white part numbers. The publication date on the sheet is 2017 which pretty much confirms they indeed made a brief appearance back then. The part number is no longer an active part number today..., at least not domestically.

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[toadman]

Thanks for the correction... I was going by what I was told & it appears that info is outdated. Doesn't really surprise me at all, but, it's good to know

 

[DSR_Phantom]

GREEN???? Wha da fu...
.
gg

green is what they come with and if a person starts having issues,there update kits come with a black one.
also with the new and improved fuel filter which I think is orange.

 

[DSR_Phantom]

Passes all tests in the shop manual including micro switch diode test. Wiring continuity passes everywhere. Latest greatest 'D' ECU (coil). New plug (have tried several). Carb and solenoid are used OEM replacements from another saw.
Harness is new. No MDG available for further analysis. (The area dealer's unit went belly up -- imagine that.) Have read everything in the SM related to the ignition, but haven't seen whether or not a bad solenoid would create a condition where the coil would not provide spark. Have also not found a workaround spark test for the ECU anywhere in the absence of the MDG unit. Don't want to risk jumping around the solenoid/micro switch and maybe damaging the ECU somehow.

Would be grateful for any experienced input or enlightenment.

Thanks.

Before i would do a lot of changing, I would go to the main part which is the coil wire. there are two places of failiure, there is a pin down inside the coil that has threads the wire screws on to thoes threads over time vibration will loosen this connection and at times even burn that pin and causing it to have no spark condition or cause a spuratic fire condition or none at all. 2. follow the coil wire up threw that channel in the saw and right where the wire goes threw the case they have been known to break into right there because of how much flex there is at that point from either pull up on a cut, of trying to pull a pinched saw out,or a lot of forward pressure on cutting. the mounts have a certian amount of give and it puts stress on the coil wire. hope this helps.

 

[PogoInTheWoods]

green is what they come with

Green was only used for a brief period several years ago. Black has also been replaced with white on MS661's some time ago which is standard now along with the new fuel filter. They're also included in theMS661 Gen3 ECM upgrade kit.

 

[Captain Bruce]

POGO knows of what he speaks. He walked me thru this exercise last Summer. The MS 661 C-M I finally repaired, is cheerfully sporting a 48" set-up, and a mill.

 

[Wood Doctor]

But, threads #97 and #98 here say it all, don't they? It is as if Sihl wanted all MS661 buyers to bring their saws right back to dealer mechanics when the spark failed to appear.