No power on Monterey 236 with mercruiser 5.7

[myboatneverruns]

I have a 1991 mercruiser 5.7 in a 1997 Monterey 236, the engine was swapped some years ago by a mechanic. I’ve brought the boat out of winterizing and had carb issues which I had a marine shop rebuild the carb, I was idling the boat for the first time this season on the driveway and the engine cut out, I tried cranking the engine too start it again but nothing happened, not even a click from the starter, now none of my accessories work including bilge, blower, radio, nav lights, wipers, cabin lights, the only thing that works is the gauges but the fuel gauge dosent read what’s actually in the tank. Before this incident it read correctly when the ignition was on. None of the fuses in the cockpit panel are blown, I replaced power receptor and ignition fuses for the hell of it. The 50 amp circuit breaker on the engine never popped. Batteries are fully charged and I have no idea what’s happening, any help would be awesome