560 XP toast

[jus2fat]

That makes no sense to me. My understanding of AT/M-Tronic is it makes near instantaneous adjustments to A/F ratio to optimize tune, ie combustion. That would seem to indicate that AT/M-Tronic could care less how much (more) oil was present. It's the rpm that determines "correct" as far as the 'puter is concerned, so all the increased proportion of oil would do in increase lubrication, at least the way I'm thinking... :msp_confused:

The "AT / M-Tronic" is just trying to adjust the carb to it's best running - -It doesn't know the gas/oil ratio

What you are saying about the 'increased lubrication' is a well commonly misunderstood thought...
(in that it's actually the opposite of what one would think)...more oil = less gas...so the saw runs leaner..Not richer)

I'm just questioning how far these "auto" adjustments can adjust..?? - there must be some limits..??

I'm thinking at 32:1 ration (WHY in a modern saw..??) was maybe just too much for the "Auto" to correct..??

Soo...1 fried piston..!!

EDIT: Or as MEUSA...above said...the 'AT' was trying to bring up the rpm's and leaned the carb even more..:msp_unsure:..??

J2F

 

[Officer's Match]

They have no way of knowing the mix, but the only way to increase RPM in the cut is to lean it out, right? Combine that with an already lean mix at 32:1 plus the fact that there have to be physical limits to what AT can do... seems plausible to me at least. Agaion, I'm just guessing here as I don't know anything about the inner workings of AutoTune.

But it isn't measuring the fuel volume, it's just going by results (rpm), therefore it's deliberately ignoring other factors. In other words, the fuel that burns is all that matters, so theoretically speaking, the more oil carried along, the more lube. Again, it's looking for output in the form of rpm.

 

[Andyshine77]

I'm thinking at 32:1 ration (WHY in a modern saw..??) was maybe just too much for the "Auto" to correct..??

Soo...1 fried piston..!!
-
J2F

If you did any research on the subject at all, you'd know why. I get the feeling you're just stirring things up for the fun of it anyway. Every AT saw that I've ran was running 32:1 mix and they likely run stronger and better than anything you have. Running 32:1 mix is not the issue here and it doesn't effect air to fuel ratio all that much.

The saw in question was either ran with too little/no oil, bad fuel, or it was running lean for some reason "air leak". From the discoloration of the piston, the saw ran this way for some time. The operator should have noticed something was wrong long ago and stopped. I see this happen with about every saw that's ran commercially or by a novice. For some reason people think if they just keep running her, or pulling the cord, all will be well.

 

[Joe Kidd]

I believe Randy has quite a bit of experience with 32:1 in the AT's. Maybe he can provide some insight.

 

[KenJax Tree]

I run all saws(AT included) and OPE 32:1 Motul 800 2T without any problems. Maybe it helps maybe it don't but i know if it grenades its not from lack of oil.

 

[Andyshine77]

People also forget the fact that fuels like Diesel are more energy dense than say 100 octane race fuel. Oil is very energy dense. Every two cycle engine engineer will tell you in most cases, more oil is better. Some even go down to 16:1 in racing engines, but that's overkill in our low output chainsaws.

 

[jus2fat]

But it isn't measuring the fuel volume, it's just going by results (rpm), therefore it's deliberately ignoring other factors. In other words, the fuel that burns is all that matters, so theoretically speaking, the more oil carried along, the more lube. Again, it's looking for output in the form of rpm.

The oil doesn't burn...it's the gasoline that burns..the oil is just the lubricant..:bang:

A 32:1 mix is just nuts in a modern saw...WHY..??...No purpose served...and Tooo-Tooo lean...= 1 fried piston

It's not the saw's fault...it was doing what it was designed to do...this is operator error...IMHO..!!

J2F

 

[Officer's Match]

The oil doesn't burn...it's the gasoline that burns..the oil is just the lubricant..:bang:

A 32:1 mix is just nuts in a modern saw...WHY..??...No purpose served...and Tooo-Tooo lean...= 1 fried piston

It's not the saw's fault...it was doing what it was designed to do...this is operator error...IMHO..!!

J2F

Think about what you just said - "the oil doesn't burn". Therefore, all the AT/M-Tronic is "looking at" is the GASOLINE (the part that burns thus effects RPM - which in reality IS what the 'puter is "looking at") The oil isn't "displacing" the gasoline, otherwise the RPM couldn't be optimized (ie the saw "tuned").

 

[jus2fat]

If you did any research on the subject at all, you'd know why. I get the feeling you're just stirring things up for the fun of it anyway. Every AT saw that I've ran was running 32:1 mix and they likely run stronger and better than anything you have. Running 32:1 mix is not the issue here and it doesn't effect air to fuel ratio all that much.

The saw in question was either ran with too little/no oil, bad fuel, or it was running lean for some reason "air leak". From the discoloration of the piston, the saw ran this way for some time. The operator should have noticed something was wrong long ago and stopped. I see this happen with about every saw that's ran commercially or by a novice. For some reason people think if they just keep running her, or pulling the cord, all will be well.

Andy..+ Officer's Match..I think and respect the world of you..!! - and I'm NOT "stirring the pot"...just my thoughts is all...

You guys take it from here...I'm off this thread...

As said...I don't own one..don't know anyone that does...soo...maybe shouldn't have posted a guess at the problem.

You guys wanna run 32:1..16:1..whatever...hey..."knock yourselves out"..as "the oil is Not displacing the gas"....:bang:


J2F

 

[Andyshine77]

Andy..+ Officer's Match..I think and respect the world of you..!! - and I'm NOT "stirring the pot"...just my thoughts is all...

You guys take it from here...I'm off this thread...

As said...I don't own one..don't know anyone that does...soo...maybe shouldn't have posted a guess at the problem.

You guys wanna run 32:1..16:1..whatever...hey..."knock yourselves out"..as the oil is Not displacing the gas....:bang:


J2F

No problem.

Does the oil replace the fuel? of course not, does some of it combust? Yes absolutely!! This is why you can't use Zinc or other metallic antiwear additives in 2 cycle engine oil, it would leave massive amounts of ash behind.

 

[MarkEagleUSA]

Therefore, all the AT/M-Tronic is "looking at" is the GASOLINE (the part that burns thus effects RPM - which in reality IS what the 'puter is "looking at") The oil isn't "displacing" the gasoline, otherwise the RPM couldn't be optimized (ie the saw "tuned").

They way I understand it, all the saw is looking at is A/F ratio and load. There are no sensors anywhere to measure anything in the intake or exhaust streams. The "brains" are simply trying to make top RPM under load. Is it not true that the only way to increase RPM under load is to lean out the A/F ratio?

I'm not trying to be argumentative or claim that I know anything about AT, but as the owner of 2 AT saws I'd like to learn more about the mysterious and magical system.

 

[jtracy1223]

Awww look at those cute lil micro brew beers and unscratched knifes. oke: around here we like cold steel and cold whiskey. But I guess every once in a while I would take a good unfiltered wheView attachment 305633at beer.

 

[Hedgerow]

No problem.

Does the oil replace the fuel? of course not, does some of it combust? Yes absolutely!! This is why you can't use Zinc or other metallic antiwear additives in 2 cycle engine oil, it would leave massive amounts of ash behind.

I have seen first hand, in a 562, massive buildup of "smut"/ carbon, over the course of just 20 tanks of use mixed at 32:1. I will not mention the oil being used, cause this is not an oil thread...
But could deposits cause excessive heat? From what I understand of auto tunes, temp is one of the inputs it can compensate for...
Right?
And did I see scuffing on the intake side of that cylinder?

 

[moody]

I have seen first hand, in a 562, massive buildup of "smut"/ carbon, over the course of just 20 tanks of use mixed at 32:1. I will not mention the oil being used, cause this is not an oil thread...
But could deposits cause excessive heat? From what I understand of auto tunes, temp is one of the inputs it can compensate for...
Right?
And did I see scuffing on the intake side of that cylinder?

I didn't see any scuffing on the intake side but I'm also on a small screen. The scoring I'm seeing looks heat related.

Call me crazy but IF the saw compensates for heat and starts going rich and builds up carbon, it'd score like that if the carbon broke loose wouldn't it?

 

[TK]

Guys, you're arguing about something you don't even know the cause of. Constantly blaming the AT for something that hasn't even been diagnosed yet. Too much energy (dense or not) is being wasted over hypotheticals and theoreticals that at this point are just plain made up!

Lets wait for an official diagnosis of the cause of burndown before getting too riled up

 

[Hedgerow]

I didn't see any scuffing on the intake side but I'm also on a small screen. The scoring I'm seeing looks heat related.

Call me crazy but IF the saw compensates for heat and starts going rich and builds up carbon, it'd score like that if the carbon broke loose wouldn't it?

I would think if the ring was doing it's job, you'd not find carbon any further than the exhaust port.
I would just be real interested to find out what caused this. If there's scoring all the way around, I'd place a bet what caused it.
Does anyone know exactly what inputs the system is looking for?
1. RPM
2. Temp? :msp_confused:
3. :msp_confused:

Where the hell is the mad professor when you need him????

 

[KenJax Tree]

I have seen first hand, in a 562, massive buildup of "smut"/ carbon, over the course of just 20 tanks of use mixed at 32:1. I will not mention the oil being used, cause this is not an oil thread...

I don't use Klotz:hmm3grin2orange:

 

[Joe Kidd]

Awww look at those cute lil micro brew beers and unscratched knifes. oke: around here we like cold steel and cold whiskey.

...and a BIG slice of pie!

 

[Hedgerow]

I don't use Klotz:hmm3grin2orange:

:msp_rolleyes:

 

[TK]

I would think if the ring was doing it's job, you'd not find carbon any further than the exhaust port.
I would just be real interested to find out what caused this. If there's scoring all the way around, I'd place a bet what caused it.
Does anyone know exactly what inputs the system is looking for?
1. RPM
2. Temp? :msp_confused:
3. :msp_confused:

Where the hell is the mad professor when you need him????

RPM.

Everything else is for diagnostics. The systems bases it's reactions on RPM alone after making a change to the mixture - which is leaning it out. If the RPM's raise, drop, or stay the same - that's the data it bases the mixture on. It only does this at WOT under load. There is a throttle position sensor so it knows. It has a temp sensor on the carb also. It does not read engine temps or exhaust temps, only carb temps.






I've seen many saws with carbon stuck rings. No comp, low power, ugly looking cylinder but can be honed with some scotch brite. Clean the groove, pop a new ring in and they're good to go. 99.9% of the time it's bad fuel and poor oil related, no matter how much the owner swears up and down it's the cleanest high test fuel and the best synthetic oil.