I would take the alternator to a rebuild shop where they can check it properly.
I know on Chevrolet's the light bulb for the charge light is needed for the alternator to work. I've also had to change the ammeter to get them to work.
The field needs excited for an alternator to work. They make self exciters for boat alternators. Check all plugs on the back of the alternator.
http://www.nationsautoelectric.com/regulators.html