Carb help: big time

[Tod59]

Need help big time with my rochester b 1 barrel carb. My phone won't allow me to use the "search" mode for some reason.
I bought a rebuilt rochester b 1 barrel carb for my 59 fleetside original 235ci. From a place on eBay. I installed carb, filled bowl with gas, used choke and truck started right up. I let the enhine warm up to about 180 degrees, slowly opened choke and truck dies immediately.....spits and sputters and dies. If (with the choke off) I pump the gas pedal a few times, restart, it starts and immediately dies. If I put choke on, it starts right up and runs fine.... until I open choke, then it dies again.
What I've done:
I checked for vacuum leaks by plugging distributor advance with a rubber plug, looked for gas leaks and even sprayed starting fluid around base and bowl looking for leaks, none found. The carburator gaskets, heat sink are installed correctly (little hole on bottom of base can breath). I also adjusted the lean and rich screw: turned it all the way in and then 1 1/2 turns out, then 2 turns out......no difference.
Please help. Since this carb is newly rebuilt, I thought it should fire right up and run.