Check valve assembly for a fuel tank filler neck

A fuel filler tube assembly (16) including a one-way valve or check valve (18). The tube assembly is adaptable for pre-assembly on either a metal or plastic fuel tank (12) and employs a common check valve (18) with an adapter tube (20) for plastic tanks. The valve employs a flapper (50) with spaced ribs (61) for deflecting a siphon hose away from the valve seal; and, the ribs are spaced to maintain the flow stream of the fuel during refueling and facilitating opening of the flapper.