Wasting ones time trying to flush the engine with fresh water, unless you can hook up a hose and run it for 15 min to half an hr. Even then, it may not flush the salt out. Especially if the Salt has worked it's way up into the gap between two mating surfaces.
The thing to do is to remove the end cap. Make sure the seal is doing what it should. If the surfaces have become pitted, then have them filed, or machined(depending on how bad, clean and flat. Re seal it with a smear of selant between the gasket and surfaces. The issue is caused by Salty moisture being absorbed by the gasket. Hence why