To avoid danger of fuel leakage into bilges of a vessel's hull, the fuel feed pipe from the fuel supply to the vessel's engine carburetor is enclosed within a cylindrical casing sealed at one end to a fitting on the carburetor. At its other end the casing is sealed to an aperture in the hull, the feed pipe extending externally of the hull between the aperture and a container enclosing the fuel supply. Alternatively the casing is sealed at its other end directly to the container. The carburetor may have an annular fuel feed chamber with adjustable fuel orifices connected to the feed pipe through a scroll valve linked to the carburetor throttle valve.