Im hoping you can help me with my problem as i have run out of ideas. I have a Yamaha 40 HP 4 stroke outboard F40Bet I was cruzing along mid speed after a few minutes the temperature buzzer sounded, with cool water coming out very well from the tale tail and at a strong pressure. I checked thermostat but it has been removed by previous owner. Still after 4 minutes on idle the temperature buzzer would beep. I have removed and cleaned the exhaust plate, changed the impeller. Switched on the engine and still on idle after around 5 minutes the temperature buzzer went off. I am honestly out of ideas and desperate to find a solution. Engine is really getting hot especially around the thermostat area. I also tried changing the temperature sensor with a new one but still no change. When i switch on the motor without the thermostat cover water flows out. Any ideas what could be wrong? really appreciate your feedback.