Husqvarna 562xp wont idle?

[david newbie]

I have no experience with computer carbs. I got this and another one from a saw mechanic who works for Stihl, he's too busy to fix these, and sold them to me cheap. I really don't have any history on these. One has a mildly scored piston, but the one I tried to start tonight has a nice piston. I started it without a bar or air filter to see if it would fire up. It does!!, but it will only stay running if I keep a finger on the throttle. I can hold the trigger lightly and it will still run ( maybe 3500rpm ish?), but if I let go it will die. Any ideas about what to do next? I'm a little intimidated about working on the carb without supervision. I might be able to get it out ( maybe ), but not so sure I would be able to reinstall it. ( I'm better at tearing apart, than putting back together). Also, is this a 2021?

 

[ballisticdoughnut]

If you’re able to do so vac/pressure test the saw. Also pressure test carb. If both pass I’d say clean/rebuild carb and see where it stands from there.

 

[david newbie]

If you’re able to do so vac/pressure test the saw. Also pressure test carb. If both pass I’d say clean/rebuild carb and see where it stands from there.

I'm fairly intimidated about removing the carb to vaccum and pressure test the saw, especially if I can avoid it. Not sure avbout my ability to reinstall it. I know I can pressure test the carb from the fuel tank end . I had an idea of attempting a reset. Cant do it by letting it idle for 3 minutes, but I think I could put a bar/chain on it and attempt a 90 second ripping cut and a log. Do you think that could be worth a try? Thanks for any ideas, and I apologize for my wussiness when it comes to working on new fangled saws . ( I ain't a young whippersnapper any more ike most of you young strong fellas.)

 

[sean donato]

It's a carb with a selinoid on the one side of it. Nothing to be afraid of. It's a bit fiddling to get in and out, but not terrible.

 

[ballisticdoughnut]

It's a carb with a selinoid on the one side of it. Nothing to be afraid of. It's a bit fiddling to get in and out, but not terrible.

Was gonna say the same. They’re really not that bad to work on, just gotta pay attention to how it comes apart. Can always take some pictures before disassembly.

 

[ballisticdoughnut]

I'm fairly intimidated about removing the carb to vaccum and pressure test the saw, especially if I can avoid it. Not sure avbout my ability to reinstall it. I know I can pressure test the carb from the fuel tank end . I had an idea of attempting a reset. Cant do it by letting it idle for 3 minutes, but I think I could put a bar/chain on it and attempt a 90 second ripping cut and a log. Do you think that could be worth a try? Thanks for any ideas, and I apologize for my wussiness when it comes to working on new fangled saws . ( I ain't a young whippersnapper any more ike most of you young strong fellas.)

If you feel like the saw runs well enough to make a cut then I suppose it’s worth a try. Only thing that would worry me personally is those saws were in the shop for a reason. The nicer of the two saws may just have been sitting for a while and whoever owned it previously couldn’t get it started with who knows how old mix in it. Just had a 545 MkII in the shop recently in that exact situation. Dumped the old fuel, purged the lines, fresh mix and thing ran like a new one. I did pull the carb apart to inspect but it was clean as a whistle.

 

[david newbie]

If there’s an air leak would that cutting reset be likely to harm the saw, or does auto tune prevent that? Guesses?

 

[ballisticdoughnut]

If there’s an air leak would that cutting reset be likely to harm the saw, or does auto tune prevent that? Guesses?

It will compensate as far as it can but eventually (and quickly) it will go lean.

 

[HumBurner]

You checked the gas lines/fuel delivery for weakness or pinhole?

One of the AF harness setups on the middle years 562s had an "open floor plan" with inferior clips that, under high heat conditions, could let go of the gas line enough to touch/rub against the carb body and wear.

There were at least three different harness/mount setups,.maybe four or more.


Edit: should have been updated by 2021, though, if all parts are up to date.

 

[sean donato]

By 21 it had all the updates to the fuel lines.

 

[HumBurner]

By 21 it had all the updates to the fuel lines.

Yep, I edited the post after I saw the mfg date. Woke up at 2am, so I'm real fuzzy today.......


Pinhole somewhere could still be causing the issue and is worth inspecting, regardless.

 

[david newbie]

Yep, I edited the post after I saw the mfg date. Woke up at 2am, so I'm real fuzzy today.......


Pinhole somewhere could still be causing the issue and is worth inspecting, regardless.

I plan on pressure testing fuel line and carb from the fuel tank end

 

[Tobystihl]

My bet is the crank bearing has lost its plastic ball spacer ring and ripped out the crank seal, I wouldn't run it again until this has been discounted.

 

[david newbie]

My bet is the crank bearing has lost its plastic ball spacer ring and ripped out the crank seal, I wouldn't run it again until this has been discounted.

how would I be able to check that? Btw, saw was rebuilt not all that long ago by the stihl mechanic who sold it to me for very cheap.

 

[sean donato]

Pressure and vac test it.

 

[Tobystihl]

Pressure and vac test it.

This

 

[david newbie]

One more question about these saws. I seem to come across many mentions of replacing carbs on these? Why would one replace the carb instead of rebuilding it? Do these carbs fail in such a way that they cannot be easily rebuilt? I will pressure test this saw when I get more time, thanks

 

[Big_Eddy]

No need to replace a carb on a 2021. Some of the original saws had an older model carb that was prone to bogs and difficult hot restarts. Not a 2021.

Check the fuel lines first, especially where the line connects to the carb inlet. then put a bar and chain on it and run it for a few long cuts. The idle can reset itself if the last time it ran the conditions were different

To pressure test, you need two plugs for the strato inlets. Husky sells them or you could fab something, maybe even corks.

 

[sean donato]

Doubt the carb needs rebuilt this soon.

 

[david newbie]

Next question, I felt nervous about tearing down a 562 that runs and starts ( but wont idle), so I decided to do a practice run on the older (2013) 562 that doesn't run, although I never tried. I managed to remove the top end and the carb, but still nervous about putting it back together.( Most of my experience is on 20-30 year old saws). On the non running 2013, I hesitate to put much money into it, as I don't feel 100% that I will get it running again. I could order a piston, or could I possibly use the current one? Look at the picture and tell me what you think please. BTW, cylinder does not appear to have scoring, just carbon tracks