Did you check Altenator ? mine did the same twice last year, both engines alt went bad within weeks of each other........ problem solved

and I actually was having the same problem with one of my spare engines that I have in the boat this year. It was constantly sounding the alarm. I changed the altenator on that too and problem went away...... my gauges always were reading 13-14 amps, but when we hook up the scanner it shows complete intermittent fluctuations in the alt. Problem seems to be solved on this engine now too..........

I think the only alarm sensors on the 575sci are high water temp, low oil pressure and low drive lube.
If any wire from one of senders grounds out, it will complete the circuit and set off the alarm

Thanks Buddy. Stuck Oil Pressure warning sensor is it .( it's stuck closed ) I unhooked all three sensors we discussed on the other motor and fired it.. No warning buzzer.. Then I unhooked the oil pressure sensor and fired this motor and wella.

Searching merc parts I only find one switch in the sensor dept.. it is the oil switch .. So this is probly the main sensor that causes this. Thanks again!