after a few days of sitting the battery is dead.It has a .33amp draw from the alternator when you unplug sense and excite wires draw is gone.not the origional alternator for the boat was replaced with an automotive one with marine cover on it thanks

Sounds like leaky diodes.
Need to replace that alternator anyway since it's not marine. Automotive alternators/starters can spark and blow-up your boat along with whoever is in the boat.