550xp strong in cut; sometimes hard to start and hesitates off idle

[treeworks59]

Husqvarna called, they are replacing the saw. I was offered a upgrade to a 562xp. The tech guy I was talking to, tells me they have cleared up early issues with the 562. They are calling it their flag ship model and would like to provide one for me to try.
I have a 65 cc saw now that gets little use. It works great but I will pick up a lighter saw every time. 50 cc seems to be the right fit for me. I now have a new 550xp in my truck ready to go. I know these are good saws from all the good results folks here on the forum report. Feeling good about trying it out.

 

[svk]

Glad they fixed you up. I'd bet this one will run well.

 

[yepper]

I'm having the exact same issues with my 550XP, guess a trip to the dealer will have to happen after reading this thread. I'm not sure if I'll ever buy another Autotune saw after all this aggravation. I've got easily 25 tanks through it at this point, started out amazing and now it just falls on its face. It absolutely cannot hold an idle without flooding. As soon as I let off the throttle it starts going chugga chug chug within about five seconds and floods like clockwork within 10. Stumbles horribly off idle if I make it to the next cut before it floods. Air filter is clean as a whistle and it revs up high once it's done stumbling so it's not an overall rich condition. This is with the HP Ultra oil mixed correctly. Ugh, what's all the performance in the world worth if it doesn't work. I'm half inclined to sell the thing as soon as it's fixed and look for a good condition 346XP.

 

[sambruin7]

Same issues here. I just bought mine like 2 months ago, it's a 2015 model. Does the really smoky starts, sometimes hard to start, and had a weird issue the other day where it would hesitate to throttle up. Another weird thing is that on warm starts the starter rope would be really easy to pull as if I pressed the decomp valve but didn't. I'm really starting to worry that I might have a piston and ring issue. I took it to two local dealers, one said it was fine and the other treated me like I'm an idiot and that I used some wrong fuel and told me to only use premix. I'm using Trufuel with Stihl oil at approx 45:1.

 

[jjsamida]

We'd been running a 550 on the pre mix and had all the above issues with off throttle and idling like crud. We used the premix because of warantee extension. Not my call .

In all our saws we run 40:1 red line race syn oil. We switched the 550 over in the middle of bucking up a tree and saw was much more managable off throttle and hot start. Been running it a month now and no real complaints from the guys ever since. Not perfect but managable.

 

[Lo Miller]

I have about 10 tanks through my 550xp. It's flawlessly strong in the cut. It's sometimes a pain to get started and running, however. When cold, it fires on choke after 3 or 4 pulls, which is okay. I immediately drop the choke off, and then it usually fires with 1 or 2 pulls -- but it often won't keep running, even though the high-idle is still set. It often takes several re-starts, letting it try to idle (touching the throttle usually kills it), until it finally keeps going on its own. It also exhausts lots of smoke during this cold starting process. I've tried it with the air purge and without, but I don't see a repeatable pattern of better or worse from using it or not.

Finally, it can take some throttle and the smoke clears up. The whole cold starting dance takes about 2-3 minutes, but it's the only 2-stroke engine I've got that takes more than 30 seconds to get idling smoothly.

The saw also has a peculiar off-idle response. If it has idled only 1 or 2 seconds since the last cut, it responds instantly to the throttle pull for the next cut. If it idles for about 5 seconds or more, you can almost hear it drop a few rpms into a lower idle state. After those 5 seconds or so, the saw hestitates or bogs just a quarter-second before responding to a full throttle input. If I give it a quick 1/8 throttle blip, the saw will die just like I've hit the kill switch (full throttle blip doesn't kill it).

On a traditional carb, I'd adjust the L screw until these symptoms went away. With autotune, however, I've got nothing to adjust. I can take it back to my dealer to look at, but these aren't major issues that keep me from cutting -- just irksome behaviors that I can work around.

Have any other 550xp or autotune owners seen similar behaviors? Any suggestions?

Thanks.

I am having the exact same issue with my 550xp. I have had it checked for air leaks but nothing was found. I think I am going to play with adjusting the L screw, it has been a fix for some. Very well described, thankyou!

 

[SmellyPirateHooker]

Low end lean condition