All that was left of the original flapper was the hinge welded to the top of the pipe. I fabricated a new flapper from a s/s strap hinge and a s/s disc for the flapper I ordered from EBay. I started this project over the Winter after talking to a mechanic that had worked on a water flooded engine with a similar exhaust as the manatee. If you attempt this fix make sure you grind off all the weld that was used to attach the hinge as it is very difficult to drill, I used tungsten tipped drill bits.