Husqvarna t 540 Xp starts and dies. please help

[Jacklefty]

hi I've got a t540 xp I'm working on for a friend that can start and then immediately dies on him. It's been to the local husky dealer twice and he's still got the same issue. Dealer says they have checked the auto tune with the computer and they say it is working as designed and has no issue. The only issue that they found is that the compression is low(85 psi). My friend is kind of fed up with the dealer and brought it to me to,see what I could find. I verified the low compression and did some searching here and the rest of the interwebs and it looks like a lot of the problems concerning the start and then dies issue is centered around the suction nipple being loose, suction hose cracking and the intake tearing. I've inspected the intake the nipple and the hose and they all look good.

I went ahead and took the cylinder off to look at the piston and cylinder since I was pretty much there with taking off the intake boot to look at the piston and cylinder condition and it looks like I can just replace the ring and scuff up the cylinder.

Along with the ring I've written up a list of parts to replace And am going to include the intake boot and suction hose fuel hose vent hose and gasket kit.

Is there anything else I should include or look for that would cause this saw to start and then die?

Thanks,
Jacklefty

 

[s sidewall]

Don't scuff up the cylinder. Replace the piston also, insurance, part of a rebuild along with the crankshaft seals.

Steve Sidwell, Samsung On5 using Tapatalk

 

[s sidewall]

Impulse line is what you are saying, comes from the crankcase and goes to the carb.

Steve Sidwell, Samsung On5 using Tapatalk

 

[Jacklefty]

Yes I'll replace the crank seals and the piston as well and yes I'll get the impulse line a step well thanks I forgot about that one.

Thanks Steve!

 

[jackjcc]

Low compression is going to hinder the impulse that drives the carb as well. So that should explain the won't stay running issue. Take some pics of the cylinder and piston and post them. Any chance your friend put old mix/straight gas in?


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[Jacklefty]

I don't know about the straight gassed but that was actually what the dealer said was the problem. But it was fresh mix 50/1 hrs an arborist and runs all of his saws in the same tank and didn't have a problem with the other three saws. So I'm thinking it's not the gas. Here's the p&c

 

[s sidewall]

Those look good.

Steve Sidwell, Samsung On5 using Tapatalk

 

[Jacklefty]

Yep that why in a bit hesitant about the repairs

 

[Ozhoo]

"Straight Gas" is what service guys say when they don't want to work on something. Often happens with autotune and m-tronic saws

 

[jackjcc]

Sure doesn't look like it should have 80psi compression


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[Jacklefty]

Yeah I know... but there are small pits along the piston ring. I would guess it sat with some condensation in the cylinder at some point.

I'll see if I can get a pic of them...

So can't get a good pic of the pits...

 

[weedkilla]

If it was mine I'd put a ring in it and run it. Sounds like you are doing the smart things for working on someone else's saw.

 

[Jacklefty]

Thank sir! I was an auto tech for 17 years and am use to doing the "smart" thing instead today the cheap way when it comes to repairing stuff.

I am hoping. To turn this part time saw repair thing into a new career.