Husqvarna 550xp carburetor installation

Installing a new AT12 carb on my 550xp, and my thoughts on Autotune/Mtronic systems.

[@jimbriney2349]

Where did you get the brass ring for the carb? I dont see it in the parts breakdown for the Husky.

[@Andyshine77]

My dealer sent it to me, I don't know the par number myself. The parts breakdown your looking at may be older, so it's not a separate part as the ring was originally part of the carb itself. If you need the part give Ashokan Turf & Timber in NY a call, Bob should be able to get the ring for you.

[@jimbriney2349]

In case anyone else wonders, the part number is 585195001. I would say if anyone is replacing the older carb with the newer one, this should be ordered at the same time.

[@Andyshine77]

@@jimbriney2349 Thanks for listing the number. The IPL I have doesn't list the number either. Did you contact Bob?

[@jimbriney2349]

@@Andyshine77 No, I found it online in the parts diagram. Just a heads up for those that dont like to disassemble before parts arrive, like me, (and youd think after all the time Ive spent working on stuff, Id know better), but the AT-7 carb is the same externally (fuel inlet being the exception) as the AT-12, so if you are upgrading from that carb, you do NOT need the brass insert, if the saw came with that carb, it will already have it.

[@Andyshine77]

@@jimbriney2349 Thank you for the update.

[@fortzosu09]

The new 550 xp model now called Husqvarna 550 XP Mark II, this new model comes with quite a lot of changes especially at the level of the cooling system where there were problems with this electronic autotune carburetor even as curious as how efficient and durable is this new model.

[@Andyshine77]

The 550 Mark II is actually not an improved version, it is an entirely new saw from the ground up, the IPL shows none of the parts are interchangeable with the old model. Husqvarna's marketing is a bit goofy if you ask me, this should be designated with a new model number like 552xp in my humble opinion. The saw also has some more weight to it, almost a full pound. Since I've gotten this 550 straightened out I actually really like the saw, incredibly good maneuverability, throttle response and power. But reliability is still concern, the new model looks to be over built, which may be a good thing.

[@TheAcenightcreeper]

I switched to echo because their warranties are better, they are cheaper to repair…i brought my 576xp into the dealer…took them a week and a half to tell me “i need a new carburetor”…didnt tell me what was wrong with the carb…just that i needed a new one…that thing only ran non ethanol…with red armor…and it was 6 years old…probably 30 hours on it total… The autotune carbs are $150…standard carbs are $50….$150 to install, so, $300 to replace a carb….$1100 saw…

[@ericsmith2239]

I just relized you helped me out on the forums with my 2253 and what to check and who to send it to thanks Andre great video

[@g.d.7629]

2253 great 50cc saw!!!

[@g.d.7629]

When you said you love the flip caps I had to respond. Lots of guys are breaking them. they should have used larger pin and HD Your plug wire is about laying on that cyclinder. Id get some clearance in there. I have about 9 autotunes with no known issues so far!! But 7 are jonsereds. I have the new 550xp markII too and I fired up 2253 jonsered they are very close.

[@Andyshine77]

First I've hear of that from anyone in the industry, good thing they have a slot for a screwdriver so you can still use them. The plug wire has a keeper that prevents it from contacting the cylinder, although it is close to the cylinder, not as bad as the 372's though they often sit in the cylinder and eventually rub through from vibration. the cylinder doesn't get hot enough to bother the silicone plug wire. The 550 MKII has been doing well indeed. Thanks for commenting.

[@CenterTree777]

Husky screwed it's customers by releasing the 550XP with soooooooooooo many issues. We were the Guinea Pigs for this saw. Doubt the 550xp MARK II will be any better, just more testing on customers.

[@Andyshine77]

I agree with you on the first generation 550. However the 550 Mark II has been out since March and has been solid, and the 572 so far has become a favorite among the loggers that that are using the. ✌

[@johnwalt3504]

I was disappointed to see on the IPL for the 550xp mark ll that it uses the same crank bearing as the original 550xp when they advertised better bottom end durability.

[@Andyshine77]

@@johnwalt3504 The bearings on the oreginal 550 were upgraded a few years ago, after that the bottom end failures ceased, so it's not surprising they went with thoes already upgraded bearings. The crank itself is new, along with the rod bearing. So far the reports are the 550 mark II has been trouble, issues with V1 550 were immediate. Time will tell how good the new 550 is, but so far so good.✌

[@lordmater]

I have a Husqvarna professional 545 Mark 2 that has fuel coming out of the exhaust. It ran absolutely fine 1 day and the very next day it will not even try to fire off. I cleaned the plug and emptied the cylinder and it still wont even try to fire off. Fuel still comes out of the exhaust if I push the primer bulb 3 times. Any ide what might be going on? I am using the 50:1 ratio fuel mix.

[@ohiyotrippole6645]

Thanks for video. Used for reference. Unfortunately, one of my strat port holes is deformed. How the F do I get the partition off it? Guessing pulling the jug is the only way as I cannot get a bit into the bottom 2 partition bolts to remove them.

[@Andyshine77]

If you're talking about the transfer covers? Yes you have to remove the cylinder.

[@ohiyotrippole6645]

@@Andyshine77 Nope. Plastic partition that holds the intake tube assembly. No way to get to bottom bolts with jug on. I managed to lose the small proprietary oring as well. I will be victorious....eventually.

[@ericsmith2239]

Bob plug that compression release they leak as well my Johnsered 2253 had transfer leak and compression release leaks and had to be rebuilt under warrenty and they plugged mine. I have since plugged all my saws release

[@Andyshine77]

Eric Smith I just bought a bag a decomp plugs.👍

[@CristiRo]

If you have a pressure tester, it can be checked very easy. I just did a check on mine to be sure. In my area the dealers sell decomp plugs for about 5$.

[@Andyshine77]

I check them from time to time, I normally see idling issues if the decomp is leaking a little. I plug all my saws 70cc and down.

[@CristiRo]

A great video to watch! Interesting thoughts as well. On the 562xp, they changed that fuel nipple direction as well, like on this AT-12 carb? I know that those are Zama, but...could this help in the hot start problem?

[@Andyshine77]

Cristi Ro As of now they have not changed that on the 562. Don't know if it has anything to do with the hot starting issues or not, it does move the line a bit further away from the devider heat shield.

[@JamesDavis-jo9tk]

Anyone that wants to should be able to repair their own saw. I had to jump through some hoops just to get screwdrivers to adjust my own carbs and now it’s firmware. I live in a right to repair state whether Husky likes it or not and will find a way lol

[@Andyshine77]

Hopefully the right to repair will some day become federal law, but with all the lobbyist I don't know if that will ever happen.

[@blomcken88]

My 550 only run when i prime it then it runs again until the fuel in the primer goes out. What may be the issue?

[@Andyshine77]

Inspect the fuel lines for leaks/pinholes, and make sure the fuel lines are properly attached at each fitting. Also test the tank vent for proper function, thus will require a vacuum pump with gauge.

[@blomcken88]

Thanks

[@g.d.7629]

Sounds like fuel line or filter clogged

[@ciphercode2298]

I've bought one these second hand and I'm having a problem. Itll start,but revs stupid high and if you touch the throttle itll die. If you feather the throttle itll run until you let off it. It's got a new piston and cylinder too. I thought maybe the carburetor boot,but I've sprayed carb cleaner around it and theres no change in rpms. Same with the clutch side crank seals. Any thoughts?

[@Andyshine77]

It still sounds like a large air leak, the transfer covers are known to leak. If you perform a pressure test, you can spray soapy water around and check for bubbles.

[@ciphercode2298]

@@Andyshine77 I'll give it a look,thanks

[@larryshulman8845]

at 757 pulled screw out? trying to get the carb out after 7 min you start but dont explain next steps?

[@Andyshine77]

It's self-explanatory after that point.

[@ericsmith2239]

Bob there's a guy on Aborist Site that can flash it for you I think he goes by Backhoe Lover

[@skilla9205]

Hi do you think that stihl MS 261C-M is better on that than actuall 550xp mark2? Thanks

[@Andyshine77]

I have not ran a 550 Mark-II, but I have owned a 261 and still own a 550 first generation. The 550 Mark-II has been going well, but it's larger and heavier than the 261, and the 261 has always been solid. I like the 261 better.

[@michaelmcphillips9241]

I’m currently working on my 550xp 2014 I’m unable to take off of the carburetor is there something I’m missing? I have the air filter off, starter cable is off. I’m unlocking the plastic hinges but it won’t come off

[@Andyshine77]

You did remove the two long screws holding on the carb?

[@michaelmcphillips9241]

@@Andyshine77 I did not I spoke to soon when I asked. I do have another question when hooking up the ignition switch back up which connector does the blue and black wire go to. When I took my saw apart last week I failed to remember which is which.

[@Andyshine77]

@@michaelmcphillips9241 Black one mounts closer to the rear handle. I believe they're different sizes and will only fit in the correct location.

[@christopherdart1749]

When you put the carb on everything just seems to fly together. Not so with mine. When I put it together the stop/choke switch refuses to move. Checed I haven't trapped the wires . Dragging my hair out with frustration. Any ideas. Would be forever grateful.

[@Andyshine77]

I'm thinking the return spring is not in the correct spot. If you look at the switch group you will see a small metal rod sticking out, there should be an even smaller wire looking rod underneath it, this is the return spring, If it's on top of the larger metal rod the switch will not function properly. It's difficult to explain, if you need me to make a short video so you can see how it looks installed just let me know.

[@christopherdart1749]

@@Andyshine77 Yes you were right, after struggling for a while I eventually spotted it. Many thanks cheers from UK

[@Andyshine77]

@@christopherdart1749 Glad I could help.

[@Ketis1985]

I wish there would be non autotune carburetor for these saws... I hate autotune. Is there any carburetor for swap? I have 2253wh.....

[@Andyshine77]

You would need a new coil and the flywheel would have to be indexed for proper timing. Also these saws are strato charged so the have strato intake ports. So realistically no, though anything is possible, as it's still just an engine, but it's definitely very difficult and not worth the trouble. Also the AT saws are now nearly flawless and I have come to prefer then to adjustable carbs.

[@Ketis1985]

@@Andyshine77 everything is possible. IIRC somebody on arboristsite has make non autotune 562xp.... on wondering if it would be possible for 550/2253 also. My 2253 has never run as good as it should always first 2 minutes it just bogs and same with my brother 550xpg which has been updated by computer. So I run other non autotune saws.... I just rebuilded 2253...

[@Andyshine77]

@@Ketis1985 Don't recall anyone running a standard carb on a 562, but yes it's possible. The v1 550 and 562 were garbage saws that never should have been sold, they were totally untested. The 550 MK-II is nice and the updated 562 is alright, if grad a Stihl of the same displacement first though.✌

[@johnwalt3504]

my carb is a at-7a

[@christiangalles9563]

Why did I take apart my dad's saw!!!!

[@dickspringfield9106]

What year is it?

[@Andyshine77]

The saw has a 2013 production date.

[@c.smythe8905]

couldnt see anything, head either in the way or out of shot

[@lucfournier3939]

All this makes me go away from getting one

[@Andyshine77]

I can't blame you. In fact the 550 is being completely redesigned and is already in testing. It looks similar to the 550, but it is a total redesigned and will be beef up, unfortunately it's going to weigh over a half pound more. Not a bad trade off if it makes the saw more reliable.

[@lucfournier3939]

@@Andyshine77 I am probably better off with àn older 254xp

[@Andyshine77]

@@lucfournier3939 Those are getting too old to use as everyday work saws, parts are getting really hard to come by. I'd look out for a 346xp or even a 353. Sad thing about the 550 is they run awesome when they run right, but that's a risky proposition IMHO. The Stihl 262 V2 is a good saw as well.

[@stihlhead3338]

You need to learn how to pronounce Husqvarna, good video other than that.

[@Andyshine77]

In Sweden it's pronounced the way I pronounced it. I learned this from my Swedish relatives.. The way most in the West pronounce it, is Americanized. If you watch the Swedish videos they pronounce it as I do. kzbin.info/www/bejne/bl67l4ptfM5ja7c Thanks for commenting, I'm glad you liked the video.✌️