Turned out to be ECT sensor on the right side of the thermostat.
Here's the confusion...When you remove that sensor lead, you are still reading water temp at the helm, so I thought that this sensor had nothing to do with anything. The sensor on the opposite side of the the thermostat, when unplugged, stopped sending info to the helm gauge, so I thought that was the only sensor associated with the engine alarm.
Sure enough, once I removed the ECT sensor lead and revved the engine up to 3000 rpm, no engine alarm. Now the question becomes, is it simply a bad sensor, or what other anomaly (slightly blocked thermostat) could be causing the alarm to kick on. Even when the alarm comes on, the engine temp is at a very safe 175 degrees, so it doesn't seem to have caused any stress on the motor...
Your thoughts are welcomed...
Lake Hartwell, GA