Good morning. First time user. I have an older 50hp Mercury. Yesterday, I stalled and made it back to shore by idle speed. When back, I noticed the black ball to pump up fuel would no get hard. Then, I noticed every time I pumped the ball gasoline streamed out of the engine into the water. The gasoline was coming from a plastic threaded tube which extends from inside the closed up engine to the exterior as if it is some kind of drain for fuel. It appears to be missing a stop nut or something. The tube is plastic and threaded. Any idea as to what part I need or an easy solution?