Alternator swap

Hello, I've been a member here for several years. I used to have a 68 mustang which I sold due to having a little one. Since then I went to a pontoon for a year, and that was enough! So I came across an 87 ski supreme Sierra ss with a cuddy cabin. It was a meet in the middle sort of thing with the mrs. So obviously I don't have a correct craft but I have nowhere to turn . To make a long story as short as possible the boat was in awful shape when I bought it. Rotted furniture, carpet,floors,stringers etc. But the motor only had 530 hours so $1700 later I had a project on my hands. I tore it down to a shell, rebuilt all the stringers with a lot of reading on this site, new flooring,upholstery,teak and everything in between. I thought I had done pretty well until mid summer of last year out on the water we heard a knock knock on the water and after tearing down the motor discovered shrapnel on two Pistons that apparently came from the intake casting, one cracked head, and a 3 inch crack in the oil valley along a waster jacket . I was able to find a good used pcm 351w out of an 87 supra with 450 hrs. $500 later I swapped the carb,distributor and a few other whatnots and got it in and running. When I bought the new (used) motor the top tab on the alternator was broken. The alternator is a Motorola 8rg2009a. I have a 3wire I believe delco from my parts motor which is an indmar btw that does work well. So my question is can that alternator work? Upon removing my broken tabbed one I had a yellow, orange and a ground coming off. My parts one had only one coming in and one coming out. I'm guessing it's internally regulated? I know that I could just buy new but I have two working alternators and I was hoping to be able to either fix my broken one or use the other if it's possible. I appreciate any and all knowledge anyone can give me on this. Thanks, Joel

According to Tim's wiring diagram, a typical PCM alternator has 3 wires, an exciter, a ground and the output. Of course, this is assuming internally regulated.

So, are they both 3 wire internally regulated alternators?



Here is an alternator wiring image that might also e helpful: