Oh Boy. :face palm: I have a 2003 Mercury 150. I just used the boat for fishing twice last week and everything was fine. I hooked up a hose to the "hose flush port" tonight to rinse the cooling system and the system is almost completely clogged. I get a "trickle" of water out of the lower case and nothing out of the pee hole. The short rubber hose between the "hose flush port" expanded from the pressure (65 psi) to a point that I thought it was going to burst. I feel like clog of this degree should be identifiable but I do not have a digram of the overall circulation system. Any simple ideas to check? Is this it for my winter Rockfish season? Thanks.