Hello everyone! Ok my 50 amp engine breaker keeps tripping while trying to start engine. The engine does turn over slightly and then the breaker trips every time. I have inspected and replaced all the main battery cables. I did a full tune up on engine plugs, plug wires, cap, and rotor button. Only thing I haven't checked real close is the wires in the main harness because they are covered and wraped up. What could be some of the things causing the breaker to trip? It's a mercruiser 454 with thunderbolt ignition.