Mike Longcor (SV Trilogy)
Thanks Joel, Bill, and everyone who has offered ideas on this topic. It's all been very helpful as I work toward a solution. I'll be taking a close look inside the injection elbow, stainless muffler, and the cylinder shaped exhaust box near the thru hull. The rubber flap is still somewhat of a mystery... if replacement is recommended, is there a recommended part source (Amel?) and procedure? I'm not so much worried about accessing it but securing it properly. Is one edge of the rubber flap fixed to the inside surface of the box right where the smaller hose comes in? Held in place with just some adhesive/sealant or something more? Or does the flap have a rigid border/frame to it that gets bonded somewhere in the middle of the exhaust box? My rubber flap is not only long gone but that whole cylinder box and reducing coupling is non-original for my boat. I don't want to re-do it the wrong way.
Any advice for getting back to the Amel standard regarding this anti-return flap is still welcomed.
Danny - I think your way of accessing it makes sense. Definitely not the easiest place to access in the engine room (or the hardest!). Also probably best done while dry unless you're floating in a swimming pool.
SV Trilogy - SM23