Mercruiser 470 Cooling

[saltydogjeff]

Is this plate suppose to be there on the exhaust manifold to exhaust elbow gasket? I think this gasket plate prevents the cooling from flowing through the exhaust manifold. It goes: exhaust elbow, gasket with holes, plate with no holes, gasket with holes, exhaust manifold.

 

[saltydogjeff]

Yes it should be.

If I understand this correctly, the exhaust elbow takes raw water and sends it down the exhaust with that portion blocked off. If it was not blocked off it would mix with the closed cooling which is located on the other side of that plate in the exhaust manifold. The exhaust manifold cools by the exiting through the exhaust cover connected to the end of the exhaust manifold.

Thank you iBoats for the help.

 

[Bt Doctur]

can you post a bigger pic on the motor and manifold ,etc. That does not look like a normal 470 riser.

 

[stonyloam]

Is this plate suppose to be there on the exhaust manifold to exhaust elbow gasket? I think this gasket plate prevents the cooling from flowing through the exhaust manifold. It goes: exhaust elbow, gasket with holes, plate with no holes, gasket with holes, exhaust manifold.

That is correct, you have the "early" style elbow. The 470 has a full closed cooling system, which means the exhaust manifold is cooled by antifreeze. The exhaust elbow and the exhaust are cooled by the raw water exiting the heat exchanger. The water flows up from the aft of the exchanger, into the elbow where it circulates around a bit to cool the elbow, and then is dumped into the exhaust passage to cool the exhaust gasses. Here is what it should look like: http://www.mercruiserparts.com/bam/subassembly/30926/1592/60

 

[saltydogjeff]

I circled the portion of the manifold. Thanks for the help.