562xp decided it won’t idle

[Big_Eddy]

My 562xp has decided this sprIng that it doesn’t want to idle any more. Started earlier this spring being a bit touchy, would only idle a few minutes. A couple weeks later now and it won’t idle long enough to set a wedge.
El48 carb. Runs great when cutting. Starts back up on fast idle, although sometimes needs 2-3 pulls where it never used to. Pulled plug and it looked normal. Clean filter, sharp chain....

Any idea what to look at first? I’ll take it in if I have to but my preferred dealer is an hour away. Local guy doesn’t impress me.

Of course no manual adjustments with Autotune.


Sent from my iPad using Tapatalk

 

[Deleted member 117362]

Have you tried a new plug. They can be plug touchy.

 

[Big_Eddy]

Not yet but it is something I’ve considered. There wasn’t a spare in my toolbox like I thought, but there is one in my sons 562 which is sitting next to mine. Next few days, when he’s not looking.


Sent from my iPad using Tapatalk

 

[Big_Eddy]

Nope, not the plug. Swapped them. His saw still idles. Mine won’t.


Sent from my iPad using Tapatalk

 

[Freudianfloyd]

My 562xp has decided this sprIng that it doesn’t want to idle any more. Started earlier this spring being a bit touchy, would only idle a few minutes. A couple weeks later now and it won’t idle long enough to set a wedge.
El48 carb. Runs great when cutting. Starts back up on fast idle, although sometimes needs 2-3 pulls where it never used to. Pulled plug and it looked normal. Clean filter, sharp chain....

Any idea what to look at first? I’ll take it in if I have to but my preferred dealer is an hour away. Local guy doesn’t impress me.

Of course no manual adjustments with Autotune.


Sent from my iPad using Tapatalk

I thought the proper method on the 562XP was to start it and immediately bury it in a log at full throttle until it learns the conditions. My 562xp doesn't always idle the first time firing it up, but after doing what I said above, it smooths out and purrs like a new saw.

 

[cuinrearview]

It might be cheaper time and gas-wise to find a member or competent dealer to send it to to get it flashed.

 

[Cycledude]

How many hours on your 562 ?
What kind of gas do you use ?
What kind of oil ?
i have never experienced that problem with mine, all I have ever used was premium 91-93 non ethanol gas and official 50-1 oil.
I always let my saw warm up a little before running full throttle or heavy load.

 

[Big_Eddy]

How many hours on your 562 ?
What kind of gas do you use ?
What kind of oil ?
i have never experienced that problem with mine, all I have ever used was premium 91-93 non ethanol gas and official 50-1 oil.
I always let my saw warm up a little before running full throttle or heavy load.

My saw likely has 300 hrs on it. Premium fuel, Husky oil, 40:1.
Before this, choke to pop, fast idle to start, run fast idle for 30 secs or so to warm up a bit, blip the throttle and idle. Cut. Idle, cut, idle, cut... Now after a cut I have about 3 secs before it dies. Big logs, no issue. Cut, blip, move, cut. I can keep a touch of throttle on as I reposition, to keep it running, but take my finger off and it stops in seconds. Starts right back up on fast idle, but blip the throttle once to idle down and dies. Fast idle, cut, throttle off, stops.

I’m done my firewood for this spring so it will likely go in soon, but I prefer to eliminate the obvious before I go.


Sent from my iPad using Tapatalk

 

[Tobystihl]

My money is on the Piston ring I've had this with t540xp's and 550xp's as soon as the compression drops off a little bit, the autotune can't keep up!

 

[Big_Eddy]

Unfortunately my compression tester doesn’t have a small enough end for the 562xp, or I’d run a quick test. Did cross my mind, however hope that’s not the case.


Sent from my iPad using Tapatalk

 

[Big_Eddy]

My 10mm adapter arrived for the compression tester.
My saw has 100psi cold. My sons newer saw has 135. After testing my sons I retested mine and reading was the same. Saw cold, throttle set to fast idle (partial throttle), 10 good pulls.

Not sure if 100psi is just low or “horribly low”. Will need to find where I hid the FSM and do some reading.

Thoughts?






Sent from my iPad using Tapatalk

 

[Big_Eddy]

Surprisingly, nowhere in my owners manual, factory service manual, or any other reference document can I find ANY specs for compression ratio or a reasonable reading for compression.
Sure - I can find process to replace ring and piston, process for pressure testing the decomp valve, pressure testing the saw and carb. But no reference to a simple compression test as a diagnostic tool, or what compression readings are within the limits. New saws seem to be running about 135, which is what my son's was reading.
So - experienced folks - what's good, what's ok, what's the lower limit of acceptable? Should Autotune for my 562XP be able to adjust for 100psi, or is it time for a rebuild?
I'll go ahead and do a rebuild if I have to - but I have more urgent tasks on my must-do list right now. If possible - would much prefer to run it for now and then do a full rebuild as a winter project.

Advice please.

 

[Cycledude]

Trade for new saw

 

[Johnmn]

@Big_Eddy the saw likely has more than 100psi compression. More often than not when you start putting adapters on and such you start to loose compression according to the gauge. A guy could pull the muffler to see what the piston looks like but before I rebuilt it I pull the carb, clean it and put a new kit in it and possibly have it "reset" at the dealer.

 

[Andyshine77]

I agree with John, if you have the wrong gauge setup with the gauge it will not give you the correct reading, both of those numbers are too low, most saws wont run with just 100psi of compression. Take off the muffler and have a look inside the cylinder to see whats really going on.

 

[irhunter]

My saw has 100psi cold. My sons newer saw has 135. After testing my sons I retested mine and reading was the same. Saw cold, throttle set to fast idle (partial throttle), 10 good pulls.

Not sure if 100psi is just low or “horribly low”.

Thoughts?

I would say, 35 psi less than your son's saw...says "horribly low." Using your terminology.

Toby, from Post #9, thinks you need a new set of rings. Me too.

Would not hurt to look through the exhaust port. Some would want a dealer to plug it in before changing out the ring.

Roy

 

[SEAM]

No small-engine manufacturer will give any specs for compression on 2-strokes...
100 psi is probably not going to work with Autotune. The gimmick can only compensate variances in fuel supply and will probably try to enrich the mixture as the drop in compression leads to a lean condition (less fuel aspirated). I once ran a 272 at 90 psi for a day or two - engine would start OK and work while cutting but stop when left idling for a couple of secs. And I did adjust the carb to the limit.

 

[Big_Eddy]

I would say, 35 psi less than your son's saw...says "horribly low." Using your terminology.

Toby, from Post #9, thinks you need a new set of rings. Me too.

Would not hurt to look through the exhaust port. Some would want a dealer to plug it in before changing out the ring.

Roy

Pulled the muffler. Good news is piston and ring look pristine. Ring is loose in the groove.
Likely going to drop by the dealer next week and have them check settings next, (and probably come home with ring, base gasket and possibly carb kit.) Unless I get bored over the weekend and go over the carb first for chuckles.

I got one picture before my phone died. Not the best lighting or focus unfortunately

Sent from my iPad using Tapatalk

 

[Tobystihl]

The only problem with Husqvarna one piston ring set up is, as soon as you get a bit of wear on the ring it results in an excessive ring gap which depletes compression. An autotune system can only really function correctly if the old school mechanicals are in order!
A two ring piston setup as fitted to Stihl etc will run a lot longer with wear before compression is an issue.

 

[r1stgei]

Have you tried vacuum testing your lines? My 562 got extremely squirrelly when I had a fuel line that needed changing. The auto tune can’t manage the file stream. Just a thought.