560xp not starting, spark OK

[mirecc]

Hello,

my 560xp suddenly stopped working. Worked fine other day and today won't even puff. First I have checked plug for spark and it's OK. Problem is that plug is still dry after most vigorous pulling session I have ever done on a saw. Tank->Carb pipes seem OK, fuel is getting into carb. I take it that it have something to do with auto-tune valve. Never serviced one of these newer units, don't know if its possible without diag tools. Anything else comes to mind that I can try to do myself before I take it to shop? Warranty period is long gone.

 

Thanks for possible advice.

[Paddy1000111]

If you dribble a little fuel into the carb/combustion chamber or you give it a TINY squirt of easy start does it fire in choke? If it's not firing at all with you manually adding fuel and you have spark then I would say to check the compression. If it's firing when you manually add some fuel then its definitely the carb 

[spudulike]

Whats the compression like? Sounds like it has gone pop. These machines seem to knock their pistons out pretty early on. Take the muffler off and take a look up the exhaust port and bring the piston up so you can see the ring and skirt - it may have some scoring on it.

These machines also don't show a lot of fuel on the plug, a seizure can cause a dry plug as can a BIG air leak but am not going to go in to the technicalities as to why!

[mirecc]

Compression seems good, measured it earlier today. I have squirted a bit of fuel into intake with syringe and it fired right up, for few seconds anyway. So it's probably carb. I ll take it to shop for diagnostics.

Edited November 21, 2020 by mirecc

[spudulike]

OK, the fact it fired means the compression is enough to support combustion. It may be the fuel pump failing the CST will test this. It may just be a bit of fine chip filling the gauze strainer!

I am sure the dealer will be right on it!

[Paddy1000111]

Good news, so you have compression/spark/timing etc. I know there's an update kit for the 560 as they had issues with not starting after re-fuelling. Something to do with breather lines, replacing the breather and blanking off a vent into the crankcase and it's available as a kit. There's also an "update" from the dealership for the computer too 

[mirecc]

34 minutes ago, Paddy1000111 said:

Good news, so you have compression/spark/timing etc. I know there's an update kit for the 560 as they had issues with not starting after re-fuelling. Something to do with breather lines, replacing the breather and blanking off a vent into the crankcase and it's available as a kit. There's also an "update" from the dealership for the computer too 

By refuelling you mean running tank dry and then adding fuel? I topped like a half tank in the morning and it never fired since then.

[Paddy1000111]

Just now, mirecc said:

By refuelling you mean running tank dry and then adding fuel? I topped like a half tank in the morning and it never fired since then.

I'm not sure of what they mean by "refuelling" I'm not a husky tech. I just know that it was a common fault and there was a tech notice with the 560xp's. Failing to start after refuelling was the notice and they bought out a kit and ECU update to fix it 

[Paddy1000111]

I can't find the tech notice but here's a post from the FCA about it https://www.facebook.com/forestrycontractingassociation/posts/husqvarna-560-xp-problems-the-usual-problem-with-560s-is-that-they-wont-re-start/682331501842512/

[Stubby]

Fuel solenoid . Replace it  to eliminate it . .