8.0kw nl gen snapping noise

[garyd]

Over the weekend while swimming off the back of the boat I heard a snapping noise seem to be louder at the gen exhaust. I turned everything off but the generator and back on one at a time it would grow fainter but never completely stopped. Wondering if anyone has had same problem.

[Jackman]

Could it be an exhaust "flapper" that keeps water from coming back into the exhaust? I don't have a genset at the moment so I'm just guessing.