Thank you so much for the information.
As I understand, I should look with Mercury for a specific connector to fit on my, say, "land hose end" that would connect to the "motor's end hose" connector?
I apologise for the redundant question. Does your Opti has a flush hose that can either be kept inside the engine's cowling or routed to outside through an oppening that is close to the other controls (wiring and cables) access?
My Opti is fitted with this sort of hose that, its other end (inside cowling) is attached to what seems to be another valve that directs the fresh wather to the refrigeration system.
All the best,