I called Indmar a little bit ago to see if they could tell me which model # alternator they isntalled on these boats, but they couldn't tell me exactly without knowing the engine serial #. They went on further to tell me that if I installed a larger alternator that I would have to upgrade the engine wiring harness, as the existing harness would not be of heavy-enough gauge to tolerate the increased load. He said that Indmar does not make such an upgraded harness, and that I would have to have such a harness custom-made at a reputable alternator/starter/engine shop. He said I most likely had a 70-amp v-belt-driven, AC Delco alternator.
Is it really this complex to add a bigger-output alternator? I am doing this only because I am installing a new stereo with 3 amplifiers (a total of about 1250 watts RMS). It isn't even that big of a stereo system. I know lots of you have added bigger alternators, and I don't recall seeing anything about needing to upgrade the engine wiring. What is the deal?