Sorry... I only half read it. AND... you should have posted in the Merc section. (I'll move the thread)
There is still a flush port, and you can run that engine out of the water, at idle speed, for as long as you wish. But... that's assuming you have enough water pressure to cool the engine. We find that some people's garden hose doesn't flow enough water, and the bulk of it goes out the pickup.
Yes... there is a single flush port, and it's still in the same location. It is a white fitting with a black cap.
Since the boat has been siting... I would recommend changing the oil in the gear case, and stator. (do a pump maintenance)