Husky 540xp mark II carburetor issues

[aarongd]

Has anyone ever successfully rebuilt a 540xp autotune carburetor?. i have 2 ea 540xp and both saws pop and skip and bog down when first started. after warms up for a minute they both run fine. Its an Walbro AT 2 729 Carburetor. I bought a new carb but skeptical to put it on cause it has to be programmed at a husky dealer. any help would be appreciated. Thx

 

[chipper1]

I have not, I actually pride myself in not doing much saw carb work.
As far as I'm aware, most all autotune carbs are similar to a standard car as for rebuilding. I've never heard that they need to be flashed/programmed after a simple rebuild.
Did you bring them into the dealer to see if they could hook them up and get the readings to be sure you're looking in the right direction? All my saws run pretty crappy when first started, but I'm guessing it's not just the basic cold saw you're talking about.

 

[cscltd]

You don’t need to reflash unit for carb work. Only if you are replacing complete carb. Search on YouTube to soft reset auto tune system via wood cutting after rebuild if you like

 

[markle]

I just rebuilt an Walbro AT carb on a gen1 550xp. Like others have said, replacing diaphragm, Mylar strip, needle , fuel screen do not change any of the electronic chip settings or stored history.
dunno age of your saw but it may benefit from a firmware update at the dealer. I’d do this before using a new carb. New husky AT carbs have no firmware installed so if you do decide to use it, take it, and your coil numbers to the dealer and ask for the firmware upload to the carb.

 

[markle]

…..and if you try the firmware update on the existing carb, they still need to know your coil ID numbers, and can print out your carb performance history (fuel settings, temps, etc) and any stored diagnostic codes. As chipper1 suggests, the printout may hint at the start of some problems that may be causing the cold start hiccups.

 

[saxon]

My goodness markle you got s bunch of saws! Do you have a favorite?

 

[ballisticdoughnut]

Any time I rebuild a mtronic or autotune carb I reset the saw to factory baseline settings. Also do any firmware updates if available. I have access to DSG-1 and CST so this is a “easier said than done” situation for most people. It’s worth doing in my opinion though.