The MS661 is for sale in the US again

[Mastermind]

Wes........did you read the post I was replying to?

 

[wyk]

Wes........did you read the post I was replying to?

Read?! Ain't got no time fo dat!

 

[Ron660]

That's not how they work. The system simply leans out the mixture every so often and watches how the rpm changes. If it goes down the mixture was too lean. If it goes up it was rich. If it goes up by just the programmed amount the mixture was just right. It can only really work at a steady throttle position, or the rpm change signal would be difficult or impossible to interpret. There may be a temp sensor, but it is not used to map the fuel mixture - the lean out test would over ride that anyway.

That's the other part I'd agree with how the Mtronics works (finding the leanest mix). I still think there's a temperature sensor to adjust for change in outside temperatures.....just like we'd have to adjust a manual carb for those changes.

 

[Mastermind]

Huskys AT system has a throttle position, and a temp sensor. These are both things I can check with their software.

I would like to think the MT system has the same.

 

[Chris-PA]

That's the other part I'd agree with how the Mtronics works (finding the leanest mix). I still think there's a temperature sensor to adjust for change in outside temperatures.....just like we'd have to adjust a manual carb for those changes.

It doesn't need to know the temperature, pressure or any of those things to compensate for them, just like you don't. It does pretty much exactly what you'd do when tuning - turn the screw a little to the lean side and "listen" to what the rpm does. And then set it back just to the rich side. Only it does that test over and over while the saw is running.

 

[Chris-PA]

Huskys AT system has a throttle position, and a temp sensor. These are both things I can check with their software.

I would like to think the MT system has the same.

I'm betting it uses the temp sensor to adjust various control loop settings - it doesn't need it for the basic mixture feedback. I also wonder if it is air temp or engine temp - since I don't have one to look at!

 

[Franny K]

Still not strato. Steel springs don't count as 21st century tech!

What is this I put the arrow on? Non gasoline mixed air?

 

[big t double]

What is this I put the arrow on? Non gasoline mixed air?View attachment 382634

Compensator snorkel.

 

[Mastermind]

That connects the back of the metering diaphragm to the air filter. The idea is that as the air filter becomes more plugged, the air fuel mixture will be automatically adjusted to suit conditions.

 

[Chris-PA]

My old McCinderblock achieves the same thing by placing the entire carb in a sealed box behind the air filter. I am kinda surprised that they still do that with AT/MT, although I guess it's one less thing the system has to compensate for.

 

[one.man.band]

magnet on/near the diaphragm?

 

[Mastermind]

No sir.

 

[one.man.band]

No sir.

gotcha. ty.

.......trying to match it published patent.

-omb

 

[Mastermind]

Niko, and a few others in the UK keep saying that Husky owns the AT tech. Have you found that to be true?

 

[Chris-PA]

No idea first hand, although I have read the same. I thought I remembered some article about Husky being told they had to share something with Stihl, but I don't remember the details nor if it was strato or AT.

 

[one.man.band]

tps feedback system (by magnet or hall sensor) to coil.....been around in autos for a while. mid '80's - '90's can't remember?

those patents are expired/freegame by all now.

newest zama patents control actual fuel flow using the diaphragm, nothing like what seems to be happening here.

 

[blsnelling]

What is this I put the arrow on? Non gasoline mixed air?View attachment 382634

That's been on Stihl saws for years. It's called Intellicarb.

 

[one.man.band]

checking into some auto sites, reveals that a tps system in an '83 toyota was run by a potentiometer, which adjusted the electrical resistance as the throttle butterfly moves. (simple 'volume' control on a stereo).

intermittent failure of tps symptoms include: poor idle; stumble.....

...in a toyota.......haha

 

[CR500]

I own a Yota T100 if that helps haha

Sent from my non internal combustion device.

 

[Ron660]

It doesn't need to know the temperature, pressure or any of those things to compensate for them, just like you don't. It does pretty much exactly what you'd do when tuning - turn the screw a little to the lean side and "listen" to what the rpm does. And then set it back just to the rich side. Only it does that test over and over while the saw is running.

I wouldn't dispute that also. When you calibrate, for 90 seconds, it's adjusting the engines rpms for ambient conditions and/or fuel mix. So it's adjusting the "idle and L" settings during the calibration. The "H" setting is probably limited.