FREDO wrote:
Some of these motors have a thermostat (my 9.9 merc does) and water will not
come out til engine reaches operating temp.

I was thinking along that line. But turned out this is not the case.
The telltail of my motor starts coming out as soon as I put the lower
unit in a water bucket. I need to make sure there is enough water
depth above the top water inlet in the lower unit; otherwise, there is
not enough water pressure and the telltail will not come out, or I can
point a water hose directly at the top water inlet to apply water
pressure.

I still don't know why the ear-muff adapter doesn't work though.

Jay Chan