debaccos

Can someone Please Help me, I have a 1999 ebbtide with a 3.0 volvo 4 cyl engine.I had a Mando Alternator with 4 wires and a ground. AN Orange wire with a short pigtail that went to a different post a pink wire a red wire and a of course a black wire. I went to a local Boat shop and they sold me a Mec 3186m-n alternator.. which I assume is a mercury alternator. Heres it the Problem. this alternator only has 3 connections. the main one I know is the orange one it goes to the stud with the insulator the other 2 come out of a harness. one black and one red. How do I hook this up? which wires from the boats wireing harness goes to where on this alternator? please help. I really want to take this boat out and enjoy it. Thanks in advance