ok Some of the mystery has been deciphered here.. 2 revelations:
so my “Exhaust adapter plate” i’ve been working on is beneath another plate called the “adapter plate” (identified in pics below), and I had been tracing how the water enters thru the exhaust plate, then thru the adapter plate, into the motor then out, I had expected the hot water and the exhaust to combine right under the engine like I’m familiar with in transoms, well guess what, the water doesn’t combine w/exhaust until it gets about a 18 inches away inside the tall muffler assembly.
But on the way there it actually exits the entire adapter plate, travels thru a hose (I’ll call it Hose-E?) then to re-enter at the muffler assembly. whew.. ok
now I had noticed that cooling water enters but has a way to get between the input water and the output pathways shown on the starboard on in the top green square of this picture. (it’s 1 inch wide but only the thickness of a gasket thick) that’s not a lot of water..but some
Then welder working on welding the plate noticed that there was/is a rogue gasket material bar on the port side (noted in lower green square in the pic above).. we have come to accept that the previous owner had actually put the gasket on
- upside-down.
Now, I since I thought water and exhaust mixed in the exhaust plate (it doesn’t) I had blocked “Hose-E” which I had figured was just overflow or something. as shown in this stock photo of someone else’s engine
so regardless, I couldn’t blow any air thru the engine cooling because it couldn’t escape since I had unwittingly blocked off “Hose-E” .
I won’t know much more till the new gaskets arrive and I do the re-assemble
