I have a Mercruiser O.E. service manual. I cannot find any procedures
or specifications for checking coolant flow at any point on the engine.
Is there a test port? If there is, does anyone know the
specifications related to coolant flow? I am going to go ahead and
replace the impeller located in the stern; however, I have a sneaking
suspicion that I will remove the unit and find no damage. My factory
service manual does not provide a test procedure for the engine temp
sensor. Does anyone know what it is. I would assume that it is likely
a resistence test. Before I go to the length of dropping the stern
drive, I want to rule out all other possibilities. I really appreciate
all of the advice. I had an impeller fail on a boat with a 5.7 L Bravo
set-up, and it was not like this. It was obvious no water was being
drawn up at that point. Like I mentioned, when I removed the
circualtion pump and hoses water poured out from all directions.