With the throttle open and the choke tight shut, you should see fuel move through the fuel line towards the carb with each hand flip of the prop. The pump should be capable of pumping fuel 3 feet straight up if all is working properly. To answer your questions, yes, sometimes dry carbs are difficult to get moving the fuel again, and yes, your carb might need a rebuild. The diaphragms inside can dry out and get stiff in a short amount of time, especially if left dry. Also, these systems will not tolerate even a tiny air leak in the supply lines. A slide on connection can seem fine, but leak air and then the pump will not work. You also need to be sure that your pulse hole in your carb adapters are lined up. That is where/how the fuel pump in the carb gets it's impulse to move the diaphragm and pump fuel. Your adapters look nice, but you may still have a problem. I made up a similar setup on a Stihl 62cc chain saw engine that I converted. I had problems with the carb mounting screws transmitting too much heat to the carb. It made overall tuning and hot re-starts difficult to impossible. I had to redesign my carb mounting so that there was no metal to metal contact anywhere to transmit engine heat to the carb.

Good luck and have fun,
AV8TOR