If anyone can please help. <br />I have a 1965 Mercury 50 HP (Model #: 1857996). This motor has two water outlets from the powerhead (bottom and top of powerhead). I was told the bottom outlet, which is below and to the left (if you are looking at the plugs)of plug #4 was to be connect to the telltale. The top outlet is a vent, which is plugged on lots of motors I have seen. The confusion I am having is when the motor is up to temperature, the water coming from the top outlet is warm, while the bottom outlet is at water temperature. 
I know this is long, please bear with me. Should the top outlet be plugged or connected to the telltale and vise versa with the bottom outlet? When the water comes from the water pump, does it go through the engine to the top of the block then lets gravity bring the water down to the bottom outlet?<br /><br />Thanks in advance!
I know this is long, please bear with me. Should the top outlet be plugged or connected to the telltale and vise versa with the bottom outlet? When the water comes from the water pump, does it go through the engine to the top of the block then lets gravity bring the water down to the bottom outlet?<br /><br />Thanks in advance!