550XP Autotune Issues..

[ajs2654]

I’m

Take the ring off and orient it in the bore the same as it would be on the piston and push it up into the bore above the exhaust port using the piston to square it up and check the ring end gap.

Honestly, it doesn’t look like it has all that much time on it to me. I think the compression is probably fine and the ring gap is probably less than .015” and their adapter was the reason for the low compression.

I ordered a new ring since I have everything apart. For 8 bucks its worth it but still don’t think it’s going to fix my issue.. I’ll keep trying.

 

[chainmaster]

Hello i don,t know if it will help since you have your piston off check the side port covers like this it,s worth a try
some times the sealer have a crack like this on the picture

 

[ajs2654]

Hello i don,t know if it will help since you have your piston off check the side port covers like this it,s worth a try
some times the sealer have a crank like this on the picture

What was the issue and how did you resolve it? Thanks for your input.

 

[chainmaster]

I could get the saw to start right i reseal with gasket maker silicone and it started better but there something else it din,t want to idle i read some where about the idle issue on the carb butterfly there is hole i made it larger a little bit at the time till i fond right spot now works great idles good and revs great it worked for me don,t know if it will work for you but you have your cylinder off check it out

 

[ajs2654]

Question.. When putting the piston back into cylinder, do the end of the rings need to go into the slot on the cyclinder? That is what I was trying to do, but in the process of doing it I think it may have moved a quarter of a inch away from the slot. Just wanted to be sure before moving forward.

 

[huskihl]

Question.. When putting the piston back into cylinder, do the end of the rings need to go into the slot on the cyclinder? That is what I was trying to do, but in the process of doing it I think it may have moved a quarter of a inch away from the slot. Just wanted to be sure before moving forward.

The ends of the ring go on the ring locating pin on the piston. The ring notch needs to line up with the pin

 

[Big_Eddy]

And don’t twist the cylinder while installing. Line everything up before putting the jug over the slug. Twisting the cylinder can force the ring to rotate in the slot and damage the locating pin. Then your ring will rotate on the piston and you will be taking it back apart. Been there.


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[ajs2654]

Well I got everything back together. I went to start and it fired right up. Compression seems better after replacing the ring. It only ran for less than a minute, and then it seemed like it was struggling for fuel. I noticed when I was primming it, it didn’t seem like enough fuel was getting to the bulb. After I am done priming it before starting, it almost sounds like there is air leak somewhere. I checked all the fuel line connections around the carb, and everything looks fine. Fuel filter was recently replaced. Well see what happens next.,

 

[mbrick]

Well I got everything back together. I went to start and it fired right up. Compression seems better after replacing the ring. It only ran for less than a minute, and then it seemed like it was struggling for fuel. I noticed when I was primming it, it didn’t seem like enough fuel was getting to the bulb. After I am done priming it before starting, it almost sounds like there is air leak somewhere. I checked all the fuel line connections around the carb, and everything looks fine. Fuel filter was recently replaced. Well see what happens next.,

Did you figure it out by now?

I had a similar issue with my 550xp. Sounded and felt like the primer bulb was sucking air and it was not filling up with fuel like normal. New OEM primer bulb and it was back in action! First one lasted 8 years...

 

[Fatherwheels]

most car injectors have to be paired to the ecu for calibration reasons, i dont think there is any way around that tbh.
its all down to ever stricter emissions targets basically
as long as the parts and diagnostics are affordable, then its just clever progress imo
2 strokes have come a long way, from 16:1 smokers with static spark ignition

Why not test the injector when its assembled and set the parameters required,
I doubt this would be difficult given its a dumb piece of equipment that opens when its told
stays there for the length of time its told, then closes, the metering and timing is done by the ecu
which adjusts to the prevailing engine needs, in my opinion there is no need for a syncing process
other than to charge for it.

 

[Khaos]

Good Morning,
So I was having issues starting my 2014 Husqvarna 550xp. Thinking it was just needing a carb cleaning, I took it to my local dealer. Unfortunately, when they looked at the saw, they alluded that they think it was related to the autotune. I got they idea they were sure how to trouble shoot or fix it. Here is the Work Order Summary:

"Performed Auto Tune but engine will not pass full throttle test.. Tested Compression.. 115 PSI(Needs to be 130-145 PSI Minimum) Checked Cylinder and it doesn't seem overly worn. Suspect Saw overheated."

I don't agree that the saw was overheated. I run a few tanks of fuel through this saw a few times year for an average of an hour use each time. I don't use any ethonal in fuel either.

My questions is where do I go next? Do I sell the saw for parts or is there a specialist out there that might be able to fix it? I am worried that if my dealer can't fix it, than no one can. I have tried asking around locally, but no one can seem to get the password to work on the autotune.

Any help would be much appreciated. Thanks in advance.

Andy

I know this is old but this may help if you still need Also let it idle for 3 minutes before performing high side tune procedure.

 

[Vintage Engine Repairs]

seems we are going the wrong way… causing more problems that we’re solving!

 

[mikethebike]

Software is in the coil, which has to be paired to the carb

corection the software is on the side of the carb in the autotune module

 

[Husky77]

Well just a status update. I dropped my saw off last week to another shop to get a second opinion on it. I got phone call today from the mechanic. In my notes, I put down issues may pertain to autotune reported by the first shop I had look at it. When he hooked it up to his diagnostics, he saw it was reading just fine so he questioning why I thought it was the autotune.. I told him about the compression reading 115 reported by the other shop. He saw he would check it out. Again, when I looked at the cylinder myself there was no significant scratches on the cyclinder other than some very light horizontal scoring and the piston looked great. Maybe the first shop didn't have an accurate compression tester..

So there might be hope!

Did the 2nd guy tell you what the compression was?
Why I'm asking is I have a 550xp runs ok but compression is only showing 50psi. Lift it with the pull cord and it slowly drops with no bar on. What puzzles me is it starts great and runs normal?