From your description of the symptoms.. I would've said it's ignition, but you say you have no fuel... how were you checking for fuel... also, can you verify the gas cap is the right one (vented or un-vented) ?? Since the pump is relatively new ( and carters have a good reputation ) I would gravitate elsewhere but, if you can open the fuel line after the pump and use some hose to go to a can or bottle, you should be able to run the motor for a minute and verify the pump is pushing fuel. And try it with the cap on and off..

Intermittant problems are always the worst!