merc 75 four stroke alarm....PLEASE HELP!!

[katama1970]

I have a 75 merc four stroke(Yamaha made for merc in 2000). I am getting an alarm sometimes when I first start it or once warmed up. I have replaced waterpump. thermostat, poppet valve , oil pressure sensor, ignition switch, plugs and wires and a burnt up regulator. I am still getting the alarm once engine warms up and idle drops. Please help as I am at wits end. I have a coild coming today that I will use to see if it is misfiring. I tested spark on all cylinders witha timing light and all looks normal aside from a slight miss on Number 2 cylinder.

 

[alldodge]

Is it a solid alarm Beeeeeeeeeeeeeeeeeeeeeeeep or a Beep every so often?

burnt up regulator.

 

[katama1970]

solid beep

 

[alldodge]

Find the Tan/Blue wire and disconnect it from the water temp sensor and oil pressure switch. If it still sounds trace the wire from the beeper and see if its is grounding out somewhere