Mercruiser manifolds and risers with dual water inlets

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jdubslopro

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I'm going to replace my manifolds and risers that only have a water inlet on the bottom of the manifold with a set that has water inlet on riser and manifold. Where does the water line connect from that goes to the manifold? From pictures I've determined that the riser is fed from the thermostat housing area (water manifold) but I can't tell where the line to the exhaust manifold goes. Should I just remove the water inlet from the riser and insert a pipe plug, and just run the manifolds in the same fashion as my current setup?
 
Don S

Don S

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Re: Mercruiser manifolds and risers with dual water inlets

What are we working on???? You may know what engine and year, but we don't.
 
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jdubslopro

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Re: Mercruiser manifolds and risers with dual water inlets

2000 5.7 mpi
0M011557
 
Don S

Don S

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Re: Mercruiser manifolds and risers with dual water inlets

jdubslopro said:
I'm going to replace my manifolds and risers that only have a water inlet on the bottom of the manifold with a set that has water inlet on riser and manifold. Where does the water line connect from that goes to the manifold? From pictures I've determined that the riser is fed from the thermostat housing area (water manifold) but I can't tell where the line to the exhaust manifold goes. Should I just remove the water inlet from the riser and insert a pipe plug, and just run the manifolds in the same fashion as my current setup?
Click to expand...

Your thermostat housing is only setup for water in the bottom of the manifold only. Not sure what manifolds and elbows you have or why they have fittings there, but they shouldn't. Are these used or what?????

I would think you should be able to take the fitting out of the elbow and install a plug, but without know exactly what you have, I can't say for sure. Can you post some pictures?

You will also need to change the gasket between them. They could be full block off gaskets on your new/used? set.
 
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jdubslopro

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Re: Mercruiser manifolds and risers with dual water inlets

I've also considered going with the newer style dry joint manifolds, but these are not designed for older motors. What about these won't work? I'm also adding a captains call exhaust system so if its just longer or shorter exhaust hoses then I consider it a non-issue.
 
Don S

Don S

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Re: Mercruiser manifolds and risers with dual water inlets

Those are really old. From back when the center rise manifolds first started. They will work if they really are any good, but you may have problems bolting stuff to them that is currently on bolted to your present elbows.
You will also have problems getting to the spark plugs to change them.
Other than that, pull the fittings out of the elbows and put plugs in them, then replace the exhaust elbow to manifold gasket with one that has 4 slots, the ones in those used ones is a restrictor gasket.
 
J

jdubslopro

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Re: Mercruiser manifolds and risers with dual water inlets

Don thanks for the reply. I decided not to go with those because of the issues you mentioned (old, spark plug changing) the guy guarantees they're good but at that age who knows for how long.

Could you please enlighten me as to why the newer style dry-joint manifolds "don't work" with the older motors? I found a fantastic deal on a set, and they're a bit more local to me. As I said before, if it's just an issue of exhaust hose length/position, I can negotiate around that as I'm also adding the captain's call.
 
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