My 06 250 Yammie 4 stroke will run like a scalded dog then you slow down and idle and the horn goes off. Turm motor off and back on no horn going off, motor runs fine. I have replaced water pump and thermostats. I went out 3 trips without horn then last trip horn goes off, shut motor off and back on no horn motor runs fine. Happened twice in a 10 hr day on the water with numerous stops. I think it may be a bad sensor. Its under warranty util december, hate to pull boat out of water now with the season on. Any ideas would be appreciated. Who is the best on the Yammies? I ran a 150 Suzuki 2 stroke for 12 years and never had any issues, got a bigger boat and now this is making me crazy.
Mike Murphy at Hanckle Marine. Yamaha 5 star mechanic. I trust him! Tell Miles or Milo, you want him, to look at it!
geechee
that motor has a pressure relief valve
if it sticks open after a high rpm run, it prevents low pressure water from reaching the top of the motor