So I recently bought a boat and to my dismay I have a crack in my left
manifold. The engine is 5.7 Merc. I'm hoping that this is the only
thing that I have to replace but time will tell. My question to you
is, should I replace both sides and the risers too? I heard that
exhaust manifolds exposed to salt water can and will deteriorate these
parts and the risers too. I believe I may also have this problem too,
because when taking out the drain plugs in the risers there seemed to
be some grime and build up behind the plugs. Open to any suggestions
that are economic as well a maintaining a well running machine.