Reply To: 1972 85 hp V4 water circulation?

[Don]

I agree, surely would not pull that water cover off the head in order to check the operation of the temp switch. But, I would surely ground the tan harness lead with the key turned “on” to make sure the horn works OK.
And yes, that tap in the block is at the top of the block, but I would think that the telltale hose would clear out any air bubbles fairly quickly. But, again, I have never tried using this port for a telltale tap on one of the older engines….
I think your plan of taking the boat to the water and trying it is the best bet. But, again, bring an assistant to monitor the telltale output just in case there is an actual cooling issue…