Pop the feed hose from the stern drive to the heat exchanger. See if water
comes out when you run the engine for 30 seconds. Alternately, you can
loosen one of the heat exchanger end caps. Those engines clatter a lot but
quiet down some when warm.
Jim
"Jim Rojas" wrote in message
...
I have a 1986 fresh water cooled Mercruiser 170HP 4 cylinder engine, that I
am trying to get repaired. I have some questions.

I am getting some tapping sounds from the front top end. How do I tell if
the oil is flowing throughout the engine? The oil gauge shows pressure.

My lower unit shows no sign of circulating water into the heat exchanger.
Does anyone know how to add a weep hole so i can visually see the flow?

Thank you

Jim Rojas