Closed Cooling efficiency

It should but sometimes the flow is not in the expected direction.
Test for overheating with all the raw water valves to the accessories closed.

 

How does the flow change direction? The raw water circuit should have a pump?

Consider spending $75 USD and put a water pressure meter on the raw water circuit.

 

This is a good catch Powerabout,
If the cap is not at the highest point, how would any trapped air get out of the system.

We have not heard from the OP since late August

 

As your engine revs, the raw water suction increases. Make sure your engine is sucking raw water from the chest and not air bubbles from the accessories pressure relief valves.

Test it by closing the raw water valves to the accessories.

 

Barry, sorry I missed your question back in October. As there was a discussion about the heat exchanger attached to a stringer, I had assumed that the discussion went in another direction. The cap is still the highest point in the system as the remote bracket places the heat exchanger roughly in the same height as if it were mounted on the motor. The hoses are lengthened and the mount puts the heat exchanger about a foot or so in front of the pulleys.