Alarm 60/40 Jet

[28shooter]

I have a 2004 60/40 jet 4 stroke. when the motor is idling the alarm goes off.
I thought it might be the water pump so I had a new one put on. Ran it the other day same thing, when running down the river everything is good. Stop and idle it goes off again. Any ideas?

Thanks MIke

[boats.net]

Have the oil pressure tested to see if oil pressure is low. Have the engine temp checked to see if it is running hot at idle.