Thanks Howie, I took your advice and gave MRC a call. Kudos to Billy. I have never spoken to him before, but he was extremely helpful over the phone, to the point of sending me pictures to help ensure my setup was plumbed correctly. Turns out the plumbing and pump are good, but something was causing a random obstruction in the fuel float valve area. The fuel float valve was stuck, making it impossible to even blow air into the fuel inlet area. After a good cleaning which included some compressed air, and re-adjusting the float, the pump is now working fine and getting fuel to the bowl.