Husqvarna 540 problem

[NickinMids]

I've had this 540 since 2014 but it has had very light use

Last year had problem with not starting or starting up but only running for a few seconds

Took it to Buxtons were it was bought from.  New carb kit etc etc and re set auto tune I think

 

Anyway the problem kept happening so kept taking it back.  Next time I used it, it ran for ten mins/half hour

then happened again.  Looked online to find that the impulse pipe might be coming off.  Took it back and

asked them to put on a new one, which they did, but problem keeps happening.  They seem to be out of ideas.

 

When its running its as fierce as ever and although I have a Stihl 150 I still need a bigger topper for bigger stuff

 

Not sure if I have to chuck it and replace but seems an awful shame.  Any chainsaw gurus advise please 

 

Cheers

 

 

 

[adw]

Stating the obvious it sounds like fuel starvation, so no disrespect to the dealer but is the the impulse pipe on properly? if you remove the starter and conducter  plate, push the rubber air tube to one side, you can now see behind the carb plate, here you can see the impulse tube, this should be firmly held both ends, I have even seen the nipple itself  pulled out from the cylinder side, if you  see no issues here check the fuel hose is not trapped where it runs under the air filter housing. Is there any sign of flooding from the carb? remove the spark plug and tip the saw, does fuel leak from the open plug hole.

[Muddy42]

I agree it sounds like a fuel starve issue. You say the issue has reappeared, so I would try checking the whole fuel system again, for example sawdust or gunk could have got back into carb (tiny guaze filter). there are plenty of youtube videos showing you how to clean out a carb. Or as above the impulse line has come off.

 

Also eliminate the simple things.  Replace fuel and air filter, clean out the fuel tank, check tank breather is sucking air.

[spudulike]

My tuppence.....same as ADW. Your symptoms sound very much like the impulse line has come off and, like him, have seem the brass nipple come out. It is possible the dealer found this and put it back with a bit of glue and has blocked it?

Other than that, a machine that age may have a bit of wear on the piston and ring. These early machines did suffer from ring wear and have had to replace them on a couple of machines as it makes the idle unstable and prone to stall.

Did the dealer give you the CST printout from plugging in the autotune? If he did, show us a pic as you can tell the running hours and more importantly, the autotune fuel settings which will show you if the machine is compensating for an air leak.

[NickinMids]

No diagnostic breakdown must have discarded

There was at least one occasion with no invoice (maybe 2) as they got it going no charge

as it kept happening

There was a piston ring replaced in July 2020 as shown.  It really does have LIGHT use

E.G. No tree work at all from end May 2022 till Dec 22.  It packed up and I took it in just before xmas

 

[Sviatoslav Tulin]

Well…….send it to Spud or ADW it’s best solution I would say.

[Sviatoslav Tulin]

I’m not very experienced in small mashinery ,but if I having not obvious problem I disassemble machine completely , usually i find a problem that way ,big dealers rarely do that if at all,so small independent Masters dealing with problem such as yours better.

[Mick Dempsey]

There comes a time when you may consider stopping throwing good money after bad.

 

You’ve put nearly half the price of a new one trying to fix this one.

 

Get a brand new one, keep it for spares.

 

[spudulike]

Best see if ADW can do it as I am not doing much now. 

Your dealer has a bit of a "scatter gun" approach to spares!

When the machine is started and you give the saw a bit of a feathering of the throttle and a few big blips to get the heat up, what does the idle do when the throttle is let off. Is it a rapid stop, a weak idle that dies or a decent idle that peters out over 30 seconds or longer?

[adw]

Any piston or ring wear on an auto tune saw and the first thing that goes is a reliable idle, there was some issues with premature ring wear but as said the idle was very poor, the saw does start and run not act like your symptoms, to be fair the T540 is fairly reliable, they are a bit fiddly to work on until you have done a few, if we are all happy the impulse tube is all good I would next look at the induction and strato tubes, if the saw has been getting stuck and you have been yanking it to free it the tubes may have split.