I bought a 2018 Nitro Z19 with a Mercury 200 hp Optimax engine. My question is related to power to fire up that engine. The boat has a 3 position power switch. Position 1 - starting battery. Position 2 - just one of the trolling motor batteries. Position 3 - both starting battery and one of the trolling motor batteries. When I try to start the motor in position 1 - it will not turn over and all power to the boat accesories goes dead. If I move the switch to position 3 - I can start the motor. Should the motor be able to start from just the starting battery? I assume this means my starting battery doesn't have enough cranking amps to start the motor. This is my first boat with a setup like this and this is probably a rookie question but hoping someone can clarify how it should work.