I just fitted a new carby on a Poulan chainsaw and for some reason it isn't sucking fuel up. It primes up and will start and run but after 30 seconds it stops, prime it again and it starts revs fine no issues but then it cuts out. Anybody have any thoughts?
Lines are up backwards Norm? Or I have been caught out with the fuel line stuck up in the tank, if you prime it on its side its under fuel level, when you put it upright it is out of fuel
Hi Tyler, it is a Poulan 2050. Lines could be crossed up, carby was different from the one I took off, original had the fuel in on side top with the return on the bottom. New carby I assumed to fuel in on the side top with the return on the bottom opposite side. Priming it I can see the fuel flowing through the lines
I had a Poulan saw that did the same thing and it ended up being the fuel hoses ,it had too tight of a bend in the hose ,worked fine when I first put the carby on then a week later the hose just would not let enough fuel through with a slight bend must be because the lines are tiny inside.
Also if you get this problem I reverse the fuel lines just to check ,sometimes you can mix them up and sometimes running the lines in reverse, then if that doesn't work put them back on the right way and it has cleared the problem. Probably gets the one way valve working for the primer also you will test the valve by it working one way and not the other way.
When the primer bubble (purge bulb) has a problem it could cause this problem if the one way valve isn't working ,I also reverse the lines on the primer if it's a remote primer and try it both ways as that can sometimes get the one way valve working again and you will see if the one way valve is stuck open as the lines should only work one way for priming.
Try it with a fuel filter that you know works fine and sometimes you can get a slight leak in the fuel hose inside the tank above the fuel level.Replace all the hoses as second hand hoses are very dodgy but you've probably done that already.
Thanks Max, all new hoses and new primer. Bit of a bitch to swap the hoses on the new carby because I have to remove the carby to get to the bottom hose but I will try swapping things around as you say. I tested the remote primer as I installed it with only the pick up hose connected to ensure it sucked fuel up
When the fuel hose is reversed the wrong way and the primer bubble is full of fuel most times the bubble can't be pushed as the one way valve stops fuel going in the reverse direction.
Yes a little bit of a pain to get to the hoses on this saw ,I have one here I can check tomorrow ,save messing around with the lines.
Pic below ,I can check if it's the same on my Poulan saw.
Thanks Max, Interesting drawing that nothing like what I had here. I assume that the top hose is the fuel in and the bent one on the lower opposite side is the return to tank line.