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Mastermind Revisits The MS261CM Type II

MustangMike

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My 362 C had fits when I changed the timing, took it a while to get used to it and like it, likely because I previously had a lot of time on it in the old timing position.

That implies to me that the function of MTronic is not that simple. I like what Dan posted, makes sense to me.

How can they say "under the same external conditions" if they don't monitor them???
 

RI Chevy

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:popcorn:

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MustangMike

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I know one thing for sure. Here in a little while I'm gonna post a video that will knock your socks right off. :D

YES!!! I was gonna post, "Aren't you supposed to be posting a video of the strongest ported 261 ever"!!!

Looking forward to seeing it Randy.
 

blsnelling

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If I've read the literature correctly they have monitored the reaction of richening and leaning the Saw under load and how the Saw reacts, they have written that into an algorithm that monitors multiple times a sec, and adjusts accordingly.

I could be wrong.
That's my understanding as well.
 

Mastermind

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My 362 C had fits when I changed the timing, took it a while to get used to it and like it, likely because I previously had a lot of time on it in the old timing position.

That implies to me that the function of MTronic is not that simple. I like what Dan posted, makes sense to me.

How can they say "under the same external conditions" if they don't monitor them???

If temperature and altitude changes, fuel requirements would change.....right?

If fuel requirements change, then it would need to reset it's saved perimeters.....right?

It's still just gotta save it's last run settings.....right?
 

RI Chevy

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Just saying, ALL Stihl saws after being ported should have to go through TEAM STIHL Captain first. So send it my way, then I will channel it to its rightful owner. Lol

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MustangMike

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If temperature and altitude changes, fuel requirements would change.....right?

If fuel requirements change, then it would need to reset it's saved perimeters.....right?

It's still just gotta save it's last run settings.....right?

No idea what the capacity of the system is Randy, but does not sound to me like it can only save the most recent setting. If that is all it did, then the literature is extremely misleading.

It says it saves settings so it can restore them when the same conditions are encountered again. That implies multiple settings are saved.
 

blsnelling

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My 362 C had fits when I changed the timing, took it a while to get used to it and like it, likely because I previously had a lot of time on it in the old timing position.

That implies to me that the function of MTronic is not that simple. I like what Dan posted, makes sense to me.

How can they say "under the same external conditions" if they don't monitor them???
Changing your timing affected the tune of the saw, simple as that. Once it ran long enough to figure out where the solenoid needed to be, it was fine.

Have you ever had an MTronic saw apart? There is nothing more to it than the coil, the solenoid, and a switch to know if it's in the "choke" position. There is no MAF sensor, no altimeter, no oil ratio sensor, no octane sensor..... The only thing it monitors is RPM and the effects tiny fuel changes have on RPMs...within a given environment, consisting of all parameters that affect tuning.
 

Adirondackstihl

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No idea what the capacity of the system is Randy, but does not sound to me like it can only save the most recent setting. If that is all it did, then the literature is extremely misleading.

It says it saves settings so it can restore them when the same conditions are encountered again. That implies multiple settings are saved.
Where is this information saved and how big is the SD card?
 

Lightning Performance

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Learning is a great thing.....and you guys have taught me a lot.

Let's kick this around a little more.

Do you understand why removing that divider screws the M-Tronic system up so badly?

Once I realized how that works, I was able to troubleshoot carb issues better.

The smaller the venturi, the stronger the low pressure signal is. So, more fuel will be forced thru the same size jet because the weight of atmospheric pressure is exerting more pressure on the fuel.

So, if we could increase the throttle plate and intake tract size, but keep the venturi the same size, what would happen to the air fuel mixture? Would more air also be pulled thru the venturi?
Stay with me now. The short side turn will always have more signal/vacuum/pulse to that side of the carb anything below WOT. Does this help you guys understand the "plate" divider? I hope so. Nothing more nothing less to learn there. I got that from day one.

I'm not sure exactly how the system picks up its feedback from the changes in air fuel mixture. If I understand it correctly, it alters mixture, then checks rpm in relation to that change. How it prevents lean out is the part I don't completely understand. I suppose if it's too lean it will lose power and rpm?
Yes, yes and yes you answered your own question.

Husky's system also uses a TPS. It's more complicated, and more trouble prone......
Not needed IMO. Just more parts to go bad. The M-tron built in MAP is better IMO. Just my 2cts

What is there to save besides last solenoid setting and maybe timing? All it has to do it leave the solenoid at it's last previous setting. Saying that it has "memory" is just a fancy way of putting it that looks good on paper. Stihl marketing is genius.
If no setting is saved the saw would run fat and timing retarded on each startup.

You don't wear socks with your flip flops?
He's a freak. They tend to wander in here ;-)
This is what happens when you keep leaving the barn door open.
 

blsnelling

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If no setting is saved the saw would run fat and timing retarded on each startup.
I'm not saying that nothing is "saved". I'm saying that only the last solenoid and maybe timing setting used is saved. It's no different than tuning your old saw right before you shut it off, and it still being in that position the next time you start it. Now, I will admit that is my interpretation of their using the word "saved". They may actually save a parameter value. But I don't read anything to suggest that it saves anything more than the last used setting. Suggesting that it does is to imply that it has more input parameters, sensors, and "intelligence" than it has.
 
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