Question concerning Genset exhaust outlet-gctid388063

[Guest]

The boat I am currently working on has a diesel genset below with a small water muffler connected and then to an outlet, just above the waterline, out the transom.

My question is, should this outlet have an external flapper to prevent water from being pushed backwards into the (small) water muffler and then up into the cylinder of the diesel engine?

Coincidentally, when I received this boat the diesel engine was siezed (bad) due to salt water left sitting in the cylinder and exhaust.

[2850Bounty]

Jim, I think that a flapper would be a good idea.

Mine does not have one, and I've thought about this several times.

It does use the water lift type muffler, and to date has not caused a problem.

I think that it would require a pretty big surge against the stern in order to force water in.

But it has concerned me.