The MS661 is for sale in the US again

[MustangMike]

The Stihl literature indicates that it does adjust for temp & altitude on start up. It would not be difficult to include those sensors in a chip. The literature also states that it remembers certain parameters based on conditions. Would think they would be open to big law suits if non of it were true.

 

[one.man.band]

guess: calibration of tps at idle, (possibly part throttle?), wfo.

IF the tps communicates with the CDI, and the CDI controls the (rate of) ignition advance curve...
it would seem that the system is based solely on ignition advance.

after start-up, if the idle RPM speed is too low, the system advances the timing to raise RPM.
(if RPM is too high, retards (hahaha) the timing).

at wfo, there may be a either a set maximum value for timing advance or it keeps adjusting the timing
until a maximum set RPM value is reached.

whatever the case, calibration is necessary to determine tps min and max values, or the
motor advance would be out of sync with RPM?

----------------------------------
another possibility, would be that the tps gizmo also houses an idle air control motor, (IAC).
the IAC motor would then control the butterfly opening. this would add complexity, and cost.
so, maybe this is not the case.

 

[Mastermind]

On the Husky system, you can perform a test that shows the TPS points.......closed....and WFO.

So, I would imagine that the Stihl system has that same ability.

Using a preset advance curve, and reading that would tell the system where in that curve the engine was at. That would allow it to "know" at what rpm it is running.....and where it should be. Couple that with the TPS and it have all the info it needs?

 

[Chris-PA]

guess: calibration of tps at idle, (possibly part throttle?), wfo.

IF the tps communicates with the CDI, and the CDI controls the (rate of) ignition advance curve...
it would seem that the system is based solely on ignition advance.

after start-up, if the idle RPM speed is too low, the system advances the timing to raise RPM.
(if RPM is too high, retards (hahaha) the timing).

at wfo, there may be a either a set maximum value for timing advance or it keeps adjusting the timing
until a maximum set RPM value is reached.

whatever the case, calibration is necessary to determine tps min and max values, or the
motor advance would be out of sync with RPM?

----------------------------------
another possibility, would be that the tps gizmo also houses an idle air control motor, (IAC).
the IAC motor would then control the butterfly opening. this would add complexity, and cost.
so, maybe this is not the case.

The only controls it has are the main fuel control actuator and ignition timing.

 

[one.man.band]

On the Husky system, you can perform a test that shows the TPS points.......closed....and WFO.

So, I would imagine that the Stihl system has that same ability.

Using a preset advance curve, and reading that would tell the system where in that curve the engine was at. That would allow it to "know" at what rpm it is running.....and where it should be. Couple that with the TPS and it have all the info it needs?

you got my vote.

 

[one.man.band]

The only controls it has are the main fuel control actuator and ignition timing.

no IAC then.

main fuel actuator .....equals tps in wfo position.... advance curve immediately switches immediately to full advance?

 

[Chris-PA]

no IAC then.

main fuel actuator .....equals tps in wfo position.... advance curve immediately switches immediately to full advance?

I've been told AT can control the mixture at other than WOT, but it would still need to be a constant throttle position. Otherwise how would it know if the rpm change it sees is due to the lean out test? I suspect the throttle position sensor is to determine that.

 

[MustangMike]

OMB, good to see UR comments, but I miss UR old avatar!

 

[SawTroll]

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

I can't prove anything, but here we go;

As far as I know, Stihl is paying Husky in some way to use it (and likely some "strato" technology as well) - but I don't know any details on the deal. Also, I understand that Stihl (UK) isn't denying it, and it is accepted as fact in the UK.
Until I'm proven wrong, I believe it is some kind of lisence agreement.

Similar info has been out in the US as well, but soon was "forgotten" about on here....

 

[Mastermind]

I can't prove anything, but here we go;

As far as I know, Stihl is paying Husky in some way to use it (and likely some "strato" technology as well) - but I don't know any details on the deal. Also, I understand that Stihl (UK) isn't denying it, and it is accepted as fact in the UK.
Until I'm proven wrong, I believe it is some kind of lisence agreement.

Similar info has been out in the US as well, but soon was "forgotten" about on here....

That makes sense Niko.....and is much different than just saying the MT system is the AT system. From the work I have done on both it is plain for me to see that they are not the same......at least not exactly.

 

[SawTroll]

That makes sense Niko.....and is much different than just saying the MT system is the AT system. From the work I have done on both it is plain for me to see that they are not the same......at least not exactly.

I would be surpriced if they were exactly the same.

 

[one.man.band]

I've been told AT can control the mixture at other than WOT, but it would still need to be a constant throttle position. Otherwise how would it know if the rpm change it sees is due to the lean out test? I suspect the throttle position sensor is to determine that.

my first question to randy was if it had a magnet on/near diaphragm. so it is not controlling fuel flow there.

i'm just throwing guesses out there. would think that the 'main fuel actuator' would be some kind of mechanical switch/solenoid. possibly its purpose is to modulate/pulse fuel flow directly. by constantly varying the opening/closing of the main jet channel?

...

 

[Chris-PA]

my first question to randy was if it had a magnet on/near diaphragm. so it is not controlling fuel flow there.

i'm just throwing guesses out there. would think that the 'main fuel actuator' would be some kind of mechanical switch/solenoid. possibly its purpose is to modulate/pulse fuel flow directly. by constantly varying the opening/closing of the main jet channel?

...

Yes, it controls the fuel to the H fuel port just like the H screw does in a normal carb. I don't know if it is a stepper motor or a PWM solenoid.

It is still basically a pretty normal carb with feedback control of the H screw.

 

[snoozeys]

I was just looking to see what a ms661 costs in Australia and they don't seem available but they have the ms660 priced at $2,099 ... leads me to believe they won't be sold here

 

[treesmith]

I spoke to a dealer in Melbourne, he said next year

 

[sachsmo]

He didn't mean sucking nutz!

 

[sachsmo]

Glad youze guys got that all figured out.

One thing that bothers me is the term advance timing.

Unless someone has figure out a way to strap Miss Cleo onto one of them modules it is against all laws of physics to have an action before it happens.

What they do is retard the timing and when advance is needed the timing is retarded less all the way up to 1;1.

Any questions class?

 

[rich450es]

any questions class? .....
i have one why is there a picture of fredy mercury and someone talking about nut suckin in this thred .......it should be in the Chris Wells thred .....lol

 

[sachsmo]

Too much pie?

 

[one.man.band]

Glad youze guys got that all figured out.

One thing that bothers me is the term advance timing.

Unless someone has figure out a way to strap Miss Cleo onto one of them modules it is against all laws of physics to have an action before it happens.

What they do is retard the timing and when advance is needed the timing is retarded less all the way up to 1;1.

Any questions class?

similar to 'multi-step retard' ? ........where a woman with 3 legs has 1 hour to buy shoes?

hope all is well 'mo.