New engine alarm system
I have a 3000SCR with twin 5.0L carb engines. My alarm system used to go off (and still does from time to time) but the Merc system doesn't tell you why. You have to check the gauges (and stern drive bottle) to see why and which engine. Really easy when you're driving at the helm. And if one of the sensors is faulty or "on the edge", the gauges won't tell you which one.
So I decided to solve my problem and I offer this solution to all those of you who are frustrated with the same problem and are handy with a soldering iron.
My engine has sensors for water temp, stern drive lube and oil pressure. When any of these sensors (6 in all for 2 engines) goes to ground, the alarm sounds. So I figured, why not put a light at the helm for each sensor??
So that is what I did. I made a neat little panel (2"x4") with 3 red LED's for the port engine and 3 green LED's for the STB engine. And they're all tied back (through diodes) to 1 alarm buzzer. (see photo). So now when a sensor goes to ground, it lights up that particular light and rings the buzzer. Perfect diagnosis!
If any of you want the circuit diagram, PM me.