My 1997 Yamaha T50 (4-stroke) is having overheating issues. Waterpump was recently rebuilt. Impeller has been inspected and looks pristine. It has good flow out of the telltale hole. Temp still gets really high and trips the overheat sensor (tested that, too; it seems to be working within spec). When sensor is removed, my laser thermometer shows the socket the sensor is in getting to 190ish, which is way too hot. Removed thermostat and tested in pot of hot water and it seems to be opening in the range the service manual said it should. I started the engine on earmuffs with the thermostat removed to see if water was getting to the thermostat, which is at the top of the engine. It's not getting to it. I am thinking this is some sort of blockage, so I removed the exhaust cover and found no blockages there, however the passage from the intake tube to the thermostat is where I can't see it. Is there a good/easy to find.clear a blockage in that part of the water passage? I've tried blowing compressed air on the waterpump side of the tube, and there is a little bit of air coming through at the thermostat passage, but seems like there should be more.
