overheating

[chuck miller]

Hi, Hope someone can help. My 1999 150hp. alarm on the left bank goes off when going around 4000 rpms. Replaced water pump, thermostats, overheat sensors. still goes off. Used a thermo Gun and the temps are exactly whats on the right band if not lower.

[boats.net]

If you are sure it is an overheat alarm and not an oil alarm then check the high pressure control valve.