Hi, I intended to use my 92 Moomba on vacation next week so I figured the prudent thing to do would be to fire it up here at home. So I hooked up a water hose to the intake hose and when I turned on the water, nothing happened at first. Then the hose blew off. I started thinking of reasons why water wouldn't circulate through the engine and I started with the water pump. I took it off and inspected it and found nothing out of the ordinary. Next in line was the thermostat, so I took it out and replaced it. I can start the boat, and it seems to run just fine but as soon as I shut the engine off the pressure builds up and blows the hose off again. Shouldn't the water run through the engine even if it is not running? Any thoughts?