Re: charging battery
your motor has, at most, a 6-amp unregulated alternator. Once you get up to 14V or so, voltage is irrelevant, it's current you need. And you need a lot more amps to keep the trolling batt charged. I mean, a whole lot more than you have. If you try to charge both batteries with your outboard, you will most likely end up with 2 dead batteries.
Due to the nature of the unregulated charging voltage, be sure to use a high quality wet-cell marine cranking or cranking/deepcycle battery. Other types of batteries won't do so well on the high voltage.