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2020/06/08 11:31:48

mattmontalto

Husqvarna 240 Will Not Start

Hello all..... new here and have a problem with a chainsaw and am out of new ideas.... I know the basics and I have verified that there is spark and good fuel... and the carb is clean as best as I can tell (I can give some detail regarding that in a moment)... but I just cannot get this thing to start....

I had run the saw out of fuel just before putting it away for the winter (and put a little stabil in and gave it a couple pulls to help preserve the carb).... then i left if in a shed for the winter... but there was some chlorine in there too and it created a oxidazation problem the severelty affected everything...

I am trying to not get bogged down in too much detail, but give enough for a good clear picture if the situation so please bear with me... as I try and cut to the chase....

So ... I changed out the ignition system entirely and the flywheel... all new and still no good... (spark plug was fine and sparking)... so I pulled out the original carb and replaced it with one I bought on ebay for 15 bucks... was the identical carb... so I went with it....

Saw still would not start under normal starting, BUT I did get it to go with the trigger being pulled for full throttle... I got that to happen repeatedly and then put the saw down to come back to later that day.... (however, it was running "rough" and would not stay running without continued throttle being given..... and when I came back to it I could not get it to go at all.....

So... being that I was always suspect of the 15 dollar carb, I pulled out out and replaced it with the original AFTER taking it apart and cleaning out all of the orafices incluing the float needle as best that I could ... I used carb cleaner blasted it out as best I could... (I dont think the carb was that dirty to begin with since I had "winterized" it anyway.

While I had the carb out, I also pulled of the housing so I could get a look inside the piston housing.... and it did not seem to have any immediate visible issue....

All back together again... still no go... next changed the fuel filter and veified all fuel lines were good and put in a new plug (and re-verified spark).... still nothing

Adjusted the idle in and out... no help.... left it set at about 2 turns out.... Next bought the spline tool.... turned the high and low all the way in (counting turns and noting them) and then tried to start with them turned in and turned out at varying amounts from the default... Still no sign of a possible start coming from this saw....

I feel that the only thing left is the piston and bore... but cant help but think that if that had been the problem then it would not have started at all when I had the 15 dollar carb in.....

Sorry for the long story... just trying to prevent wasting anyones time with a back and forth on stuff that has already been done....

Can anyone tell me what I can try next.... or what I can do to verify if it is a problem with the piston.... Thank you..

I also hav loads of pictures and some video and if it would be helpful, I can make them easily available to view. Thank you

8 comments Leave a comment

TownsendsFJR1300

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2020/06/11 16:45:07

mattmontalto

Scott,

Thank you for your reply. I did confirm there was spark with the plug grounded to the block.... I also tried doing a little squire of engine starter fluid in the spark plug hole and still got absolutely nothing. I have to see if I have something that can fit my tester to that size spark plug hole to do a compression or leak test, but it just boggles my mind that I am getting nothing at all in response.... I cant imagine the piston is that bad that I cant get anything at all... but this could be my lack of experience speaking.... I looked at the piston from the intake side and it really did not look all that bad.... however I havent seen the exhaust side yet.... I am contemplating just pulling out the block to get a better look at it and the piston, but just trying to get any opinions that may help first.... ... Thanks again for your help.....

Matt

2020/06/12 08:59:30

AVB

You will at 100 psi for the engine to fire. And yes the PNC can be that bad.

Carburetor Initial setting of both L and H is 1-1/2 turns from lightly seat, Adjust H after warn up so you get a little 4 cycle sound.

As pulling PNC you will get good idea of condition by looking at the exhaust side. Scoring is a bad sign of PNC damage.

PNC = Piston and Cylinder

2020/06/12 11:01:56

mattmontalto

AVB

Thanks so much for the response and info... really appreciate the good advice.... Basically I have been trying to avoid having to pull out the whole block if there was some other direction that I should be looking.... but unfortunately that is where all signs seem to be pointing.... not that I totally hate doing it... will be a good learning experience.... just dont like doing things when they are a waste of time... thanks again for the help and info....

Matt

2020/06/12 11:27:10

AVB

mattmontalto
AVB

Thanks so much for the response and info... really appreciate the good advice.... Basically I have been trying to avoid having to pull out the whole block if there was some other direction that I should be looking.... but unfortunately that is where all signs seem to be pointing.... not that I totally hate doing it... will be a good learning experience.... just dont like doing things when they are a waste of time... thanks again for the help and info....

Matt

That is pulling the muffler is better, saves us techs a lot of time. Especially when the customer doesn't want to spend much on the saw.

Another way I look through plug hole but most you can't see upper cylinder damage that way; unless, you using an inspection scope camera with a right abgle mirror attachment. At least this saw doesn't have the 10mm plug, very few inspection scopes camera will fit these but more are showing up lately on the market.

2020/06/12 11:35:10

mattmontalto

AVB

Sorry for the delay in response... busy weekend..... Thanks again for the advise... Like you said, I could see very little through the plug hole, but I did get a chance to pull the muffler and take a look and (to me) the piston did not look bad at all... I cant say I can verify the cylinder walls since I cant see them, but I would think that if they were damaged there would be more piston damage as well....?

I tried to make something up to use my pressure tester to adapt to the spark plug hole so I could check compression but I couldnt get anything to fit it, but in doing so I keep thinking in the back of my mind, that I can certainly "feel" that there must be a decent amount of compression based on the resistance when I pull the coil with the sparkplug in (as opposed to when it is out)..

Not sure if that is a bad assumption but coupled with the very little amount of wear I see on the piston, I feel its at least somewhat logical.....?

2020/06/15 09:50:19

AVB

According the IPL it has a standard plug hole at 14mm and most compression includes this in their kits. The Actron tester I have even included the 10mm adapter.

Details about Champion RCJ7Y:

Threaddiameter: 14mmThreadreach: 9.5mmSeattype: flatHexsize: 19mm

2020/06/15 10:31:10

mattmontalto

AVB
Thanks very much for sharing the helpful info.... really appreciate it....

Matt

2020/06/15 10:50:06

- OR -

Husqvarna 240 Will Not Start

According the IPL it has a standard plug hole at 14mm and most compression includes this in their kits. The Actron tester I have even included the 10mm adapter.

Details about Champion RCJ7Y:

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