What was found
(CAN) FUEL HEATER HAS AN ACCESS PORT INBD THAT IS NOT USED ON THIS INSTALL AND A LOOSE METAL SHIPPING PLUG HAS FOUND INSTALLED INSTEAD OF THE REQUIRED STEEL MS9902-04 PLUG LOCK WIRED IN PLACE. THE LOOSE PLUG ALLOWED FUEL TO LEAK INTO THE LOWER COWL AND OUT THE DRAIN AND THAT IS WHAT WAS NOTICED PRIOR TO LANDING. THE CORRECT PLUG WAS INSTALLED AND SECURED, THE ENGINE GROUND RUN WITH NO LEAKS FOUND.