The pin has a knurled end and a reduced size end. Insert the pin from the starboard side to the port side, reduced size end first, catching the float arms. Be sure you get the needle valve into the fuel inlet hole and be sure that the tiny little spring remains clipped to its' tab on the arm. The pin must be pressed into final position. I used a "C" clamp ("G" clamp to folks on the east side of The Big Pond) to carefully press the pin home.