power flushed, both the engine and the manifold (from the output of the water pump as well as the aft drain port)... lot's of stuff came out. I did notice that the flow thru the block when flushing thru the water pump output hose was MUCH less that when flushing thru the drain plug.

I removed the temp sending unit (with a BIG pipe wrench) ... as expected, there was a little "capsule" of hard, crusty crud surrounding it. I broke that up and cleaned that out as best I could. Then power flushed exiting the temp sensor port.

I acid flushed ... twice .. oodles of dark, greenish, blackish junk came out ...

On top of all of this, some boat backed up into the pier and severed the water supply to all the boats just after the power flushing .. so I was fetching water from the marina restaurant for the acid/flesh water flushes.

There is a very significant change now in the amount of water flow out the tail pipe .. at medium rpms .. it really flows like a 1/2 open water hose.

Temp gauge now showing 110-120 deg with bypass valve shut (100% flow thru engine).