Mercruiser inboard 1980 Chris Craft Raw water cooling flowpath

[kenimpzoom]

So, I finally got all the parts and the thing back together. Raw water pump fully rebuilt.
Here is the problem, the exhaust manifolds get too hot. At least 200F seems hot to me.
So, I want to make sure this thing is plumbed correctly.
I already confirmed the thermostat works properly.
No water in oil.

Flowpath:

1. water hose from house
2. Raw water pump
3. Trans cooler
4. Intake manifold
It splits in multiple places here...
Front part leads water to engine water pump
Rear part (below thermostat) bolts to intake manifold - four hoses lead out, two lead to elbows and the other two lead to the rear exhaust manifold water inlet (or outlet?)
Rear part (above thermostat) two hoses lead to front of exhaust manifold
Note: In between the exhaust manifold and the elbow is a plate with only a tiny hole in it


My question is, how exactly does the water flow through the exhaust manifold. Are the hoses at the front and back both inlets and then the water flows through the elbow and out the boat exhaust. If so, why is there only a tiny hole in that plate to let water flow? Is this the wrong plate?

Or is the hoses at the front of the exhaust manifold the inlet and the rear is the outlet?

 

[Bondo]

Ayuh,..... Hard to tell in yer picture, where does the in-coming water from the raw water pump go into the t-stat housing,..??

That big bar hides alot,...

 

[alldodge]

Looks like you need to move a couple hoses. The 2 coming off the very top section of the thermostat housing should go to the rear elbows

 

[kenimpzoom]

Ayuh,..... Hard to tell in yer picture, where does the in-coming water from the raw water pump go into the t-stat housing,..??

That big bar hides alot,...

Input from raw waterpump goes into the housing pictured here. Lower hose, below the engine pump hose.

 

[kenimpzoom]

Looks like you need to move a couple hoses. The 2 coming off the very top section of the thermostat housing should go to the rear elbows

View attachment 380575

Thank you thank you thank you....This diagram is awesome. I agree, the top two should go to the elbows and right now, they are wrong.

 

[kenimpzoom]

Thanks everyone, that fixed the problem. Manifolds stay around 140-150F now.