Abstract: Disclosed herein is a cap assembly for a fuel tank including a cap having a top wall with a vent opening therethrough, a cylindrical side wall depending from the top wall, a generally cylindrical wall depending from the top wall and inside of the side wall, and defining a recess therein, and an insert in the recess. The insert includes a hollow generally cylindrical member defining a bore having opposite ends, one of the ends being closed and the other of the ends being open and adjacent the top wall with the bore being in fluid communication with the vent opening. The insert also includes an annular flange surrounding the generally cylindrical member intermediate its opposite ends, the flange having a periphery engaging the cylindrical wall, and a hole in the flange for providing fluid communication between the fuel tank and the recess.