Weber carb swap

[mpqualdie]

I see alot of info and replies on the Weber carb swap. I put my 85 motor in my 86 720, so it's been a little bit of a challenge. I finally gave up and bought the conversion kit. The truck starts up and runs great... well to it warms up a little (a few minutes) then it just die as if someone shut off the key. It won't start back up for quite a while. Yesterday, I sprayed starter fluid in it and it ran great as long as I sprayed the starting fluid in it, then it would die again. let it sit for a while and it starts right back up. It's almost as if the temperature of the motor has something to do with it. Does anyone have any ideas on what could be causing this? The kit tells me to vent the carb through the charcoal canister still, could this not be working and causing a vapor lock in the float of the carb or something? Every thing else has been disconnected already, as the wiring is different from the 85 (motor) to the 86 FI (body). I am running the old fuel pump from my 85 and have about 3.25-3.5 lbs of fuel pressure. Thanks in advance for the help.

[PEZi]

How old is the pump? Is the fuel relay working properly? How are you running your return line / are you running a return line?

My best guess off hand is fuel relay. I thought for the longest time that mine was vapor locking because it had what seemed like all of the symptoms, but it turned out the relay was just crap.

[mpqualdie]

The pump wasn't working at all at first, so it is wired to the ignition hot for now. I read something in the service manual that the pump won't run if the oil pressure sending unit is faulty and I have manual gauges on mine now, so I just wired it to the ignition hot. I got it to work and it runs great now. I saw a post here where the fellow said to put a smaller tube in the return line to put a little more pressure in the line. I set out to do that and realized the incomming and return lines were switched. I didn't know it would make a difference since they go to the same spot, but the return line is a little smaller and that must be what it was because after I switched them, it runs great now. Thank you all for the ideas and help!!