562/555 off idle hesitation remedy
- Thread starter mweba
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moody
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Glad you finally posted this. There's been a few threads of recent people asked about this and I posted your video.
mweba
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I resurrected an old laptop that for some reason allows me to sign in. Tapatalk just loads and loads, Chrome browser on Android won't let me sign in. Think I've managed four posts since the hack.
Any who, what is the other thread that you embedded the video?
M
moody
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562 questions I think. There was another thread I think page 3 or so of 261 or 550 thread. I let people know it was your video and your fix. Just posted the video to help them out. I'll dig around and pm you the links if you'd like
M
moody
Guest
I can only log in from my droid but not the laptop. I'm not real sure what the deal is. Still trying to figure out the new platform
mweba
Addicted to ArboristSite
The Autotune controls one solenoid. Like standard carbs, the low pressure flowing over the main nozzle shifts the fuel draw to the high side. The AT learns to control this transition through the Throttle Position Sensor. Knowing when the pressure changes passages in the range to alter the fuel flow at the solenoid.
Bog at idle can also be caused by a rich condition. To test for this, let the saw idle for three to five minutes. If it loads and blows smoke/unburnt fuel, its rich. Possibly the needle isn't seating proper or the pop off was adjusted to much. The condition this fixes is a lean one. From the factory some of these carbs throttle butterfly is sealed to tight, not letting enough air past. In turn, the AT leans the mixture to attain the proper idle speed. If one is to let more air by, more fuel is necessary to maintain the same idle. The 550/545 Walbro carb has a bypass adjustment screw.
550/545
Untitled by mweba1, on Flickr
Untitled by mweba1, on Flickr
In
Untitled by mweba1, on Flickr
Out
Untitled by mweba1, on Flickr
Bog at idle can also be caused by a rich condition. To test for this, let the saw idle for three to five minutes. If it loads and blows smoke/unburnt fuel, its rich. Possibly the needle isn't seating proper or the pop off was adjusted to much. The condition this fixes is a lean one. From the factory some of these carbs throttle butterfly is sealed to tight, not letting enough air past. In turn, the AT leans the mixture to attain the proper idle speed. If one is to let more air by, more fuel is necessary to maintain the same idle. The 550/545 Walbro carb has a bypass adjustment screw.
550/545
Untitled by mweba1, on Flickr
Untitled by mweba1, on Flickr
In
Untitled by mweba1, on Flickr
Out
Untitled by mweba1, on Flickr
I appreciate the work Mitch has done on this. I am curious as to what Husqvarna's official response to this situation is? I may be wrong but it seems like mweba has come up with this on his own which is very smart of him. Certainly Husqvarna must have a service bulletin on this situation. Are these the official steps that should be taken or is there more to the story that the Manufacturer isnt telling us? And for you dealers out there, what does resetting the fuel settings do? Is this a reflash with updated software or is this just resetting the learned parameters. It seems like the latter would be a temporary fix. Im just trying to understand this situation better. I can't imagine I'm the only one that has a problem with taking a grinder to a state of the art carb on a saw that costs $800 bucks when the warranty period isn't even up yet (If it hadn't been voided by having it ported!) I wish I understood this carb better (that may NEVER happen)
mweba
Addicted to ArboristSite
All I did was implement what was learned via the 550 carb air bypass adjust screw. Knip here, tuck there. Trial and error. If your saw is under warranty, by all means take it in. I use this on ported or out of warranty units.
As for Husqvarna's official response, when I called tech to inquire about the 550 screw, they said it does not exist and there is NO adjustments to the carb. Now, obviously I'm looking right at the screw.....They asked me to send pics and responded that it is no an adjustment. Have they updated their stand on some info recently, they may have but I don't bother to call much anymore. We have stock in inventory that still has the EL46 so I've not seen the new AT carbs.
Are they Walbro? I'm looking it up now.
I actually did take my saw in to TK last week. He was going to reset the computer. He said it would be ready at the beginning of the week. I just need to go pick it up and see how it is. I have no idea whether its under warranty or not, I bought it ported with 2 tanks run through it earlier this year. I'll contact the original owner and see what he knows about it. It just seems strange that Husky doesn't have a service bulletin on this. Maybe they will put a link to your youtube video in their service information 
