550xp mk2 dies at full throttle under load

[treemuel]

As title states, my 550xp mk2 (stock) just started cutting out at full throttle under load. First noticed it with the saw on its side in a face cut; thought it was out of fuel, but wasn't. Checked the air filter, fuel filter, both clean. Noodled a log to do the autotune reset. Seemed to run fine for a bit, then happened again. Possibly only happening once it warms up...? What should I check next? Thanks!

 

[Wood Doctor]

Could be the ignition module. Sounds like it's an electrical problem of some sort. Check all cables and connectors.

 

[huskihl]

Wouldn’t hurt to check the screen in the carburetor. Sometimes they get plugged up with stuff inside the filter

 

[Wood Doctor]

Unfortunately, removing the carb on a 550 XP is not the easiest venture but huskihl is right, that could be a problem area. There is even a YouTube presentation on it.

 

[Tomos770]

Unfortunately, removing the carb on a 550 XP is not the easiest venture but huskihl is right, that could be a problem area. There is even a YouTube presentation on it.

 

[Motorka]

GENUINE OEM FUEL FILTER FITS HUSQVARNA 540 545 550 555 560 562 592 572 503443203

503443203 Part#: 503443203 Description: FUEL FILTER Description Specification Name Brand FUEL TANK 592 XP® Husqvarna FUEL TANK 592 XP® G Husqvarna FUEL TANK T540 XP® Mark III Description Specification Name Brand FUEL TANK 540 XP® Mark III Husqvarna FUEL TANK 545 Mark II...

www.sawsalvage.co

 

[Tomos770]

Blue filter is for AT saws....has finer mesh..

Husqvarna Fuel Filters

How often you need to change the fuel filter depends on how much dirt there is in the fuel. Our recommendation is to check and, if necessary, change fuel filter every 100 hours or every month. Husqvarna have implemented a new fuel filter with improved filtration, for there Auto Tune™ products...

pennsperformancesaws.co.uk

 

[treemuel]

Thanks for all the replies. I pulled the carb apart (it certainly is one of the more PITA carbs to remove that I've encountered) and cleaned the screen, although it didn't seem particularly dirty. Anyway, got it all back together and initial results are that everything is working great. I do wonder if there's some particular set of conditions that will cause it to act up again, but I've got a big job on Fri to give it a real test and hopefully it doesn't crap out on me up in the tree again, lol.

Maybe I'll go ahead and order one of those new fuel filters in any case since neither of my local shops had even heard of their existence, haha. And the one on the saw currently looks after market (I bought it used).

 

[JRHAWK9]

This guy is the tech at one of WI's larger Husky dealers. About 1.5 hours from me.

 

[HumBurner]

That's good info, thanks!

What's the deal with these new fuel filters? I've had a few AT saws and they all came with the stock all-white fuel filters that have been used for 10-20 years. Why do AT saws all of a sudden need these new filters, and why specifically AT saws....why not all the saws IF it filters better?

 

[Motorka]

better filtration

550xp mk2 dies at full throttle under load

As title states, my 550xp mk2 (stock) just started cutting out at full throttle under load. First noticed it with the saw on its side in a face cut; thought it was out of fuel, but wasn't. Checked the air filter, fuel filter, both clean. Noodled a log to do the autotune reset. Seemed to run fine...

opeforum.com

 

[HumBurner]

better filtration

550xp mk2 dies at full throttle under load

As title states, my 550xp mk2 (stock) just started cutting out at full throttle under load. First noticed it with the saw on its side in a face cut; thought it was out of fuel, but wasn't. Checked the air filter, fuel filter, both clean. Noodled a log to do the autotune reset. Seemed to run fine...

opeforum.com

Lol, I get that.

What I'm asking is why now? Why not 12 years ago? Why does an AT carb need a separate filter from the new orange-tipped filter or the old stock-white filters?


Edit: also, is Husqy going to swap out all my old fuel filters for me?

 

[Motorka]

Blue filter is available for year or two?

 

[HumBurner]

Blue filter is available for year or two?

Sure. And AT saws have been out since 2010 or 2011, so..........?

 

[huskihl]

Lol, I get that.

What I'm asking is why now? Why not 12 years ago? Why does an AT carb need a separate filter from the new orange-tipped filter or the old stock-white filters?


Edit: also, is Husqy going to swap out all my old fuel filters for me?

Metallic shavings from the fuel were getting through the filter and plugging the carb screen

 

[HumBurner]

Metallic shavings from the fuel were getting through the filter and plugging the carb screen

Okay, but then why the need for two filters, one specific to AT saws? If an AT carb and a standard carb are essentially the same aside from the electronic component(s), what's the difference?

And were the 3-series saws having this issue with the older style filter? If not, why?

This is where I'm lost.

 

[treemuel]

Ran like a top today. So I’m guessing there must have been just enough little gunk in the carb screen to bog it down at wot.

Wrecked out this split Poplar with it. Glad it didn’t leave me hanging

And XS 7900 for the win on the stump

 

[Wood Doctor]

I'm working on another one: Husqvarna 550 XP. I rebuilt the top end because no compression remained. After the rebuild, it started and ran twice, but it refuses to restart when warm. I think I need to take down the carb and inspect it also. I seldom run into this after a complete rebuild. It's a bit frustrating, but this is my first encounter with an AutoTune saw. If anyone has any ideas, please advise. TIA.

 

[Tomos770]

550 mks1 had/has tandency towards hard restarts when warm....

Heat can build up inside its carburetor and they evolve vapour lock...

Whenever you put it hot to the rest...pop up its cylinder cover to cool it down...

Or leave it idling for minute or two....then restart it with fast idle!

Put some additional holes in cylinder cover for additional cooling...look for late style mk1 covers for reference

Do a MMode.....so that saw will breathe more easily (less heat build up)

 

[Tomos770]

Sorry for the "marketing" part...but its informative!

550XP next steps

After a bunch of lurking and gathering what knowledge I can, I'd like to ask a question of the experienced folks here. I have a 2016-bought gen 1 Husky 550XP [s/n 2012 5000658] 966 64 82-00] that's currently in "starts-occasionally or not at all" mode. It's been a a pain in the ass since new...

www.arboristsite.com