As noted, give it time on the test bench, and make sure it is plumbed correctly.

Even though it is a pumper, tiny bit of fuel foam can cause havoc. When they go through the pump regulator, the bubbles accumulate, and can cause larger air bubbles in the carb feed line.

And I too will get in line.... if you decide to get rid of it I owned 4 of those at one time.

Bob