Overheat buzzer comes on randomly on one of my twin yr 2000. 150 Yamaha outboard

[Shersea2013]

I have installed both overheat sensors on the one engine that over heats. I have used a laser thermometer on each each head. One head was 128°. The other was 138°. I can use the boat all day and not have a problem. Seems like it happens more when boat is idling. Does anybody have any idea what is the problem?

[jiggin joe]

RE:

You might want to check the pressure control valve on that motor. They can cause overheat at low rpm if not functioning properly.
J

[Shersea2013]

Is the PVC the same as a poppett valve?

[jiggin joe]

re valve Pressure Control

Yes same thing. Don't forget to change grommet while your at it as most times it is the problem.

J.

[99yam40]

PCV or PRV would be my thoughts