Finally have both my spare 575sci's installed together. Ran it like that for the first time yesterday. Boat ran flawless, better then my original motors. Only issue is the buzzer wont stop ringing when both engine keys are in on/run position. When I shut either engine the buzzer stops. Temp is perfect, voltage is fine, drive bottles full, and oil pressure is perfect....... Scanned both engines and no fault codes at all. Neither engine is setting off the alarm. Anyone ever have this happen ? Maybe a faulty buzzer ? Just weird it didn't do it last year with one original and one spare motor running.

Are the wires to the drive lube bottles still hooked up?

Yes...

The mefi 3 monitors the following:
Low oil pressure
Low Drive oil
engine over heating
low voltage

I suppose you went through a shut down and restart deal also right? Just a basic reset. I use to have this happen once in a great while and for the life of me can't remember the problem. It may have been the drive resivor tanks/bottles mentioned in above post. But I would imagine it had something to do with install. Wasn't that way before but is now. Did you clip off a sensor/sender or something lowering new install? Ground? Possibly buzzer itself but I doubt it. Just start process of elimination. Glad all at least went well and it was nothing obvious. You'll find it

Yes, that's why I'm confused.... all those readings are fine. Scanner says that no alarm or light is being set off. I will have to go back and check all the grounds again..... and possibly install new buzzer...... I'll keep you posted..... Thank you for the help.........

I suspect one of the wires going to the buzzer is grounding out somewhere.

Most people just clip the alarm wires and sell the boat.

I had that problem with my 500efi's and it was that the float in the drive lube bottle was stuck down. The bottom of the bottle was all gummed up. Drain the bottles and clean it out. That might be your problem to

Do you have a fuel vapor sensor? When the sensor fails it triggers false alarms all the time. Replace sensor - alarm goes away.