Mercruiser 7.4 MPI - Intermittent steady beep. (drive fluid alarm with new bottle)

[711KMD]

Aye - So, I've got a 2000 Mercruiser 7.4 MPI. First start up of the season, I had a steady single beep alarm. Yes, the Outdrive fluid alarm. Cleaned and refilled old bottle, no change. New bottle, no change. After banging my head through this that and the other, I started noticing it would not beep sometimes depending on which battery I started on. When it does beep, it idle's like crap. RPM's surges and almost dies like my old carbed 454 when it was running crappy, voltage surges, all other systems fine. I eventually figured it would always start and run fine on battery 2, never on 1 or both. It got me through. I'm out of the water now and it just beeps every 3 out 5 starts. I got it running right and then ground out the bottle wires, I got the alarm to sound, but it did not stop when I broke the ground. It also beeped again after restarting. It never stops once it starts no matter what I do.
I've attached my Diacom report. The alarm sounds weakish sometimes like it knows it should not actually be on. The engine runs amazing when it starts right. I almost want to think it's in my ignition switch as it's the same test alarm as powering on the ignition, it just doesn't stop after engine starts.
Thanks for any thoughts

 

[tpenfield]

Greetings . . .

The first thing to do is resolve all of the codes. (3 codes were found)

However, at first glance, based on your engine liking one battery vs. the other, it would be a good indication that you have a bad battery. The codes also indicate voltage problems.

I would test the suspect battery and replace as needed. You can certainly test the voltage into and out of the ignition switch, but the battery would be top on my list, given that everything is fine when running on the other battery. See where that leaves you and go from there. It is a process of elimination.

 

[711KMD]

Greetings . . .

The first thing to do is resolve all of the codes. (3 codes were found)

However, at first glance, based on your engine liking one battery vs. the other, it would be a good indication that you have a bad battery. The codes also indicate voltage problems.

I would test the suspect battery and replace as needed. You can certainly test the voltage into and out of the ignition switch, but the battery would be top on my list, given that everything is fine when running on the other battery. See where that leaves you and go from there. It is a process of elimination.

Appreciate it. One of the batteries is actually new, replaced alternator and belt, but fully agree on the voltage issue, but sort of lost even where in the elimination process to start at this point with the inconsistency trying to repeat it. Thrown a MAP and IAC sensor at it. Trying to work the codes for sure. Frustrating thing is only so many things are wired to the alarm, but I must have tweaked something somewhere to trigger it.