261 M-Tronic - What makes it tick.....

[breese]

As I continue to evaluate the 261 M-Tronic, I will update this posting with that information and pictures as they become available and I understand what it is.

I received a few coils and a carb from @big t double. Thank you again..

Looking into the carb first, it appears this entire configuration talks thru what is known as a 1-Wire communication (getting access to the CPU will verify).
This 1-Wire allows for both asynchronous (bidirectional) data transfer and supplying power to the slaves (carb, etc) although this is somewhat limited but then again, we are talking chainsaws.....

As a reference, there are Weather Stations designed to use this communication method with a number of different devices / slaves.
http://archives.sensorsmag.com/articles/0698/wir0698/index.htm

One downside to what I am seeing with the wiring and connectors, any misuse or corrosion will affect the data transfer / communication between the CPU/ECU and slaves.

 

[Adirondackstihl]

 

[Wonkydonkey]

 

[Mastermind]

Pass the popcorn bishes.

 

[Wonkydonkey]

help yourself, I think we could be here a while

 

[breese]

So the carb is interesting....
There is a connector that allows the System to be reset...
Then there is the Solenoid....
This has me a little confused on how or what it actually is doing.

Carb with the Computer connection




As you can see, the "Solenoid" has 4 holes
I can only assume this is some method of fuel regulation


But what is interesting is the hole do not seem (yet) to line up
within the carb....


Need to think on this one....

 

[breese]

Teaser!!!
Need to do a few other things BUT
This thing is Smart!!!

This is only Half of the circuit board

 

[paragonbuilder]

Subbed!

 

[MustangMike]

I definitely have to get on board!

 

[Locust Cutter]

 

[retro]

 

[TreeLife]

 

[Cigmaker]

I'm dumb.. but watching.

 

[Adirondackstihl]

I'm dumb.. but watching.

 

[fin460]

I still don't even have traditional carbs figured out, but I'm still interested.

 

[Cracker Boy]

Just picked one up non runner im boarding this ship.

 

[Cracker Boy]

Found it on craigslist for 75 needs cleaned up couple smalls gonna replace fuel impulse and seals if bearings ok and rering it if piston and cylinder good.havnt looked at it shes not locked up.never worked on one before.chain was on backwords though.

 

[retro]

Teaser!!!
Need to do a few other things BUT
This thing is Smart!!!

This is only Half of the circuit board

Yep, that PCB is way more conventional than I envisioned! Perhaps...

 

[retro]

So the carb is interesting....
There is a connector that allows the System to be reset...
Then there is the Solenoid....
This has me a little confused on how or what it actually is doing.

Carb with the Computer connection
View attachment 90227

View attachment 90225

As you can see, the "Solenoid" has 4 holes
I can only assume this is some method of fuel regulation
View attachment 90226

But what is interesting is the hole do not seem (yet) to line up
within the carb....
View attachment 90224

Need to think on this one....

The solenoid operates by pulling on the sealed piston to uncover the fuel supply port in the bore of the carb. I think you'll discover that one of those ports in the bore is a fuel supply (from the fuel pump) and the other is a return line. The brass in the bottom of the bore is probably the jet that supplies the metered output fuel to the high speed nozzle circuit.

Everyone calls it a solenoid, but thats a generic word thats tossed around far too often while describing similar devices. It would make more sense to me if that is actually a variable position plunger being pulled open (against a light return spring or not) by a small electromagnetic coil. If so, technically it is not a solenoid, its an electromagnetic motor.

 

[Dub11]