2010 Mecury Optimax 150 Alarm Sounding?

[buckbuster2004]

I have a 2010 Mercury Optimax 150 2 stroke. We changed the water pump and L/U oil about 75 hours ago. Today while on the water the boat would not run over 30 MPH without the alarm sounding. It appears that the water pump is still good because it has a solid stream of water coming out and the motor does not feel hot after running for a period of time. We also made sure the oil level was full. If you stay under 30 MPH it will run all day with no alarm. This is a first for the boat and I'm not sure what it could be, maybe a sensor? Any help would be appreciated. Thank You

 

[schematic]

Re: 2010 Mecury Optimax 150 Alarm Sounding?

The appearance of the stream means very little. Check the engine temp with a infrared gun when alarm goes off.
Best to check the pump visually. Even though its only 2 years old, it could be damaged by running dry....