hi i have a 1997 yamaha 75hp two stroke that a constant alarm goes off at trolling speed. if i bump up the throttle just a little bit from the trolling speed it goes off after a minute or so. have run the engine all day and does great until i slow down. water is peeing fine and doesnt feel hot to the touch. havent had it run hot in neutral before just when i put it in gear. anybody have any suggestions? i'm thinking it may just be a sensor but not sure