I got my tstat replaced and my 50 hp johnson is still overheating. After starting, it takes like 15 seconds for water to come out of the tell tale. Also, after about 5 minuted of running, the overheat alarm sounds. Where the water comed out the exhaust holes, just below the tell tale hole, there are two slots, but water only comes out of one, not even any air comes out of the other one, could this mean something? I think I will try a new impellor, maybe adequate water isn't getting to the motor. Any thoughts?