On my 1999 150hp Johnson I replaced the water pump because when I removed the plugs for the thermostats while running their was no water coming out. After replacement still has no water coming out unless you put your thumb over the center port to restrict the water coming out the center port. I noticed this port is threaded so is their a re-stricter that screws in this port? I just bought this boat and want to make sure I have no problems when I go to Gunnison Colorado in June.