Or, you could simply inspect the manifolds and risers very carefully to
determine IF they need replacement. It's very possible that an otherwise
good manifold with a crack could be repaired for a reasonable cost. It's
almost certainly worth checking out.

If you are at all handy removing and inspecting the manifolds and risers
should not present a problem. That should permit a god inspection. If you
need replacements your labor is not wasted and if not you will certainly
KNOW the condition of your system for the cost of gaskets, time, and some
skinned knuckles.

Butch
"JIMinFL" wrote in message
hlink.net...
Replace your entire exhaust system. It's just part of normal maintenance.
Jim
"397ce" wrote in message
oups.com...
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.