The 572XP Update Thread

[andyshine77]

The new gen should adjust really fast, within a cut. And in my experience the old gen would adjust in a few good cuts. IMHO something else is up, what I don't know. One thing I note, the two 572's I've ran, including the one I have, seem to idle too low for my taste.

 

[ZERO]

I'll have to do some fact finding on that one.

Where does the part throttle reset come into play that @afleetcommand showed in his videos? I have never seen anyone mention this.

Is it my correct understanding that gen 2 of ATs take parameters at idle and part throttle thus they set much quicker than the gen 1s that only took WOT parameters?

 

[afleetcommand]

Throttle "reset" really is just letting the saw have time to "tune" itself at a given throttle position. Think of it this way, there is a throttle position sensor, and at some percentage of opening and above auto tune shoots for max rpm's, and at the lower "part throttle" positions or opening percentage, it shoot for A given rpm. At idle for example with "zero" percent from the throttle position sensor it's going for what ever Husqvarna determined was a good idle number. Maybe in subsequent updates that changes. SO start it , giving it some arbitrary opening like 25 percent, autotune will "iterate" the fuel setting to work at that percentage opening to a given rpm. Then in the first cut where the throttle opening percentage is past that point where it's going for max RPM's yet again autotune will iterate until it gets to the max rpm possible in those conditions....and then while it continuing to do that "testing" thing, from the user perspective the running characteristics have become steady state. It's running good..... and as was pointed out the newer versions are faster than some of the older ones to get to those "tunes". But the take away is just run these things. Warm them up as always so u don't cold seize them and cut wood. Appreciate on the cold days not having to worry about a too lean condition is how I deal. I've been running mine this winter and loving the fact while it may start out a little choppy when I go from a day at 10 degree's to the next at 40, I don't have to tweak the carb....25-30 seconds of me standing there does that vs.me fumbling with my gloves trying to be a good mechanic

 

[ZERO]

Walt thank you for that detailed response. Just had a logger buddy pull out his backup 572 stock after sitting for 6mo complaining about sluggish respomse and near death idle. I gave him the part throttle trick that you memtioned along with some WOT cookie cutting that @Stump Shot mentioned after warm up and the problem went away. I tried to explain that for a new landing, the change in temp, elevation, humidity, and fuel, AT had to get re-callibrated.

He never knew about the part throttle reset, he could feel the saw change in RPMs after 30s to 40s with the same load and throttle position as demomstrated in your recent video.

 

[afleetcommand]

Bob gets wound up with the terms "part throttle" and reset because it really is a tuning process and not analogous to a firmware change ....because in CST the lower than "max rpm" range in operating history is labeled "part throttle"
SO I don't know. How about less than 1/2 throttle or simply leaving it in "high idle" to tune "low speed" setting and more than 2/3'rds throttle with a load to keep the RPM's reasonable for full throttle setting or.....a freak'n Cut that lasts more than 20 seconds. U get the concept and that really is all that matters to me. I actually pulled two video's and rehashed one to get the terminology "correct"

 

[RI Chevy]

Good info! Thank you sir.

 

[Cooper264]

I got a 562 used and was a little weary of the AT carb junk as it was my first saw with a computer in it. Every time I start it it kinda spits and sputters for about a minute and then figures itself out after that. I never really thought about leaving it at say high idle for a sec to let it tune itself. Might help it some. I absolutely love the saw

 

[ZERO]

Walt all great points, always enjoy the videos where you and Bob cut some wood, have a BBQ lunch, and chat about both the past and the latest and greatest.

We may all have different angles on the terminology, the end game is the same: trying to understand more what AT does behind the scenes.

To look at the example that @andyshine77 mentioned with the low idle, could this be the break in period where AT is holding the saw back and richening up the idle mixture till it gets past the break in clock? Just a speculation on my part as I should have asked for the accumulated time. I remember my 1st 562 not behaving the best at idle in the beginning. It was only here that I learned about AT holding the saw back till a certain time frame. Once I got to my MK1, yup same behavior, this time I knew what to watch for and after about tank 8 or 9 when the saw got its full power, all idle and start problems went away.

 

[M2theB]

Walt all great points, always enjoy the videos where you and Bob cut some wood, have a BBQ lunch, and chat about both the past and the latest and greatest.

We may all have different angles on the terminology, the end game is the same: trying to understand more what AT does behind the scenes.

To look at the example that @andyshine77 mentioned with the low idle, could this be the break in period where AT is holding the saw back and richening up the idle mixture till it gets past the break in clock? Just a speculation on my part as I should have asked for the accumulated time. I remember my 1st 562 not behaving the best at idle in the beginning. It was only here that I learned about AT holding the saw back till a certain time frame. Once I got to my MK1, yup same behavior, this time I knew what to watch for and after about tank 8 or 9 when the saw got its full power, all idle and start problems went away.

If that’s how it works, a break in margin built in, I wonder how the saw would act if say after 20 tanks through it, I decided to have a Master Reset done on the carb. For whatever reason.
Would it start over with a break in feature?

 

[John7478]

One thing I note, the two 572's I've ran, including the one I have, seem to idle too low for my taste.

I love the low idle of the 572, reminds me of the 046/ms460 idle.

 

[afleetcommand]

If that’s how it works, a break in margin built in, I wonder how the saw would act if say after 20 tanks through it, I decided to have a Master Reset done on the carb. For whatever reason.
Would it start over with a break in feature?

Doesn't matter if u master reset or not, it's going to iterate from where it is to where it needs to be regardless. All those settings are in flux as the saw tunes it self. All a master reset does is put it back to defaults & erase history. Unless there was a big problem where the numbers were way off it isn't needed. I guess if major components have been changed and you want to erase the old reporting /history and have a "fresh" start on history a master reset makes sense IF u have CST to read and track that stuff. But Even then ( numbers way off ) it will work it's way to the right settings once the base issue is corrected. Point is once the carbs have firmware, unless there is a update to the firmware that matters, most of us really don't need CST , dealer, or anything related to the computer

 

[big_eddy]

I believe a reset does not reset the hours on the clock.
In which case once the break in is over, then a reset will not restart the low hour hold back period.


Sent from my iPad using Tapatalk

 

[andyshine77]

My 572 is well broken in, it actually seemed to get a little lower the more I used it. So far it only stalled once after I set her down after starting it cold with a change in the fuel mix, so that was on me, other than that it has never stalled while anywhere near warm and fires up in one pull warm, though at times it can sound like it wants to stall. If I had to guess the idle could be bumped up with a firmware update if needed, for my saw it hasn't been a problem, I'd just personally prefer a slightly higher idle rpm. I'm nitpicking on this one for sure.

 

[Duce]

Glad you said it first. I want a saw that not only idles, revs, chain stays sharp, cuts great and it can clean itself when I put it away. Now that is wishful thinking and nitpicking.

 

[huskyboy]

I checked both the 572xp and 372xp here with a tach. They were both at 2600-2800rpm. Maybe 572xp just has a choppier lower sounding idle than a 372xp because of the longer stroke? No idea honestly. I just cut wood with my saws.

 

[ZERO]

Walt I do agree with you that a software update is only necessary where it matters, and that did matter to me on the MK1 and the 562 back in 2018. Prior to that both saws had what I can only describe as a low fuel start state, just as many have described here, sputtering for a while before settling down and running fine. This was after both saws got the WOT re-set or re-tune regiment that @Stump Shot mentioned. On the 1st fire back from the dealer I could instantly tell both saws had a more richer loaded up sound in the low and mid rpm range. At the time, I did not realize how much this update would help with cold starts and hot re-starts, but because this condition corrected both saws, i knew this was not a placebo effect. I am sure that other parameters were re-tuned as well.

A little off topic: @Cooper264 I would go back and re-read @Stump Shot's statement from P20 very carefully, think of a zip tie or a tape around your throttle, between cuts you are not letting you finger off the throttle, let the saw bounce off the rev limiter between cuts. For the cold starts or re-starts, do not use the decomp, always have high idle set she should fire right up. If I remember correctly @huskihl mentioned a while back about how the manual choke and decomp is fighting what AT is trying to accomplish which jumped out at me because I remember how not well my restarts went. Then Walt mentioned it in one of his videos which re-confirmed what @huskihl said and my painful memories of start and re-start mishaps.

 

[andyshine77]

I checked both the 572xp and 372xp here with a tach. They were both at 2600-2800rpm. Maybe 572xp just has a choppier lower sounding idle than a 372xp because of the longer stroke? No idea honestly. I just cut wood with my saws.

Could be, never bothered to put a tach on the saw.

 

[John7478]

Could be, never bothered to put a tach on the saw.

There is only 100rpm difference between the 572 and 462

 

[Eccentric]

I like these...

 

[John7478]