I have a 502 mag efi that I just reinstalled after a transom assembly changeout. I just fired it up last night to make sure all is well. Everything looked great other than the annoying alarm sound. Does anyone know what all triggers that alarm on this engine? I am assuming it will trigger on oil pressure, temperature, and drive oil resivor. Is there anything else? Also what are the alarm setpoints? Thanks in advance!!

Those are the only alarms that I know of on that engine.
Oil pressure is about 7#
Water temp is around 200*

You probably have an alarm wire that is grounding out.

Thanks! I will look into the possible grounding issue.

Does anyone know if you unplug any of the 3 sensors will it make the alarm go off all the time or will it not go off at all. Ive got a friends boat that the alarm goes off up on plane but not idling. The water temp is right at 170 oil pressure is 40 and drive bottle is full. Was wondering if we could unplug the sensors one at a time to try and diagnose. ANyone try this before?

Almost sure it is drive oil, unplug and it should stop. All the sensors ground to make the alarm go off so unplugging will make the alarm stop.

Unplugging the sensors will make the alarm go off.
If it does not go off, then one of the alarm wires has a short and is grounding out.

I have seen trim sensor mistaken for drive lube bottle ground... simply switched around

Sure enough... It was the drive oil. I thought by simply shorting it together would make it stop. But it didn't. Installed the outdrive, filled with fluid, and all is good. Thanks everyone!