Guys,
I'm stumped and looking for some wiring help regarding a 2 volt drop somewhere in my 2006 Outback V with the Indmar 310 Carb engine. I replaced both batteries today thinking my old batteries may be the problem but the problem persists. When you turn the key to acc or all the way on on I drop to roughly 10.3 volts to all of the gauge panel which is causing the perfect pass stargazer wake edition to absolutely go bonkers cutting on and off.
I am getting a 12.5 or 12.6 volts reading at both batteries and the same at the bus bar under the instrument cluster.
I read on here that some of the older Moomba's had a Medallion controller that controlled the gauges but i'm not sure that applies to 2006 OBV. Is there anything y'all have heard of that may be causing a 2 volt drop or any other location i should check? I'm assuming its a grounding issue somewhere, but not sure where else to check.

I've cut the main lug to my perko and clamped a new connection on it. I've used a battery brush to scrape and clean all connection on the battery (+ and -) and Perko. I'm doubting it's the alternator as if it were bad I don't think i'd be getting 12.5 volts at my bus bar.

Any other suggestions of places to look?

Thanks
Ryan