T540 XP & 420 when hot hard start

[Dennis Aitken]

T540 XP & 420 when hot hard start. I can use one for about ~20 minutes then shut it down while I am cleaning brush and maybe putting it into a burn pile for another day. Anyway... After I put it down (handle up) I grab it and try to start it and after many, many, many pulls the @#$% doesn't want to start again.
So I'll grab the other one and work ~20 minutes and the same. Same thing happens BUT when I grab the first one it STILL won't start.
Maybe it is telling me that because I am old I need a break BUT there is work to be done and there aren't any elves around here.
It is quite embarrassing when you are volunteering to help clear a victim's driveway or the PD is waiting to get through the street.
I could really use advice.

 

[Franny...K]

Firstly make sure you don't have winter formula gas in your mix. I think this may be because they put the fuel tank at the rear near to the muffler. The 338xpt and other saws with the same sort of spark plug pointing at the operator have the fuel tank at the front. The 542 battery saw is the cure though in the summer heat you may need a few batteries and a cooler to put them in if you have a lot of sawing to do continuously.

 

[Leon Couper]

Could be a number of things but could br yopur coil breaking down when hot.
Does happen and more than you think. Either that or could be getting a bit as you
were saying wanting a rest. If you have got a compression gauge try it while it
is hot and see what that comes too.

 

[Pratt_ty]

Try letting them cool for a few minutes, then use a few short pulls with the choke partially off. Also check the carb heat shield and idle mixture sometimes these XP and 420s get finicky when the engine is hot.

 

[blades]

I have run into this problem a few times. for me it generally has been vapor lock. when you stop cutting , set saw aside still running for a bit that allows it to cool down a bit.