1985 200hp Yamaha. I replaced the water pump, lower seals, and the thermostats. Went out once and everything was fine. Second outing and pisser stopped and alarms went off and engine stopped. HMMM. So after a good cool down I started it up and limped home with a small pisser. So I got it on the muffs and a great stream came out about 6 foot of strong water. Then it all about stopped and came back without any change in acceleration. What could it be???