What was found
I HAD A NEW ELECTRONIC FUEL PUMP INSTALLED. AT START UP IT SEEMED TO FUNCTION CORRECTLY. I PRIMED THE ENGINE AND THEN MOVED THE FUEL PUMP SWITCH TO BOOST AND STARTED THE ENGINE NORMALLY. WHILE TAXIING TO THE RUN UP AREA AND THE FUEL PUMP SWITCH IN THE BOOST POSITION, I COULD AUDIBLY HEAR THE BOOST PUMP SPONTANEOUSLY ENGAGE INTO PRIME MODE AND THE ENGINE IMMEDIATELY BEGAN TO FLOOD AND QUIT OPERATING. I MOVED THE FUEL PUMP SWITCH INTO THE OFF POSITION AND THE ENGINE STARTED TO RUN NORMALLY AGAIN. EACH TIME THAT I TRIED TO PUT THE ELECTRONIC FUEL PUMP IN BOOST MODE IT WENT INTO PRIME MODE AND THE ENGINE WOULD QUIT. THERE WAS FUEL UNDERNEATH THE AIRPLANE. MY A&P DETERMINED THAT THE BRAND NEW WELDON FUEL PUMP WAS FAULTY AND WAS RETURNED TO THE MANUFACTURER. MY AIRCRAFT IS CURRENTLY AOG AND AWAITING A RESPONSE FROM THE PUMP MANUFACTURER.