In this forum, we do not need to know what type boat you have, we need to know the following to answer your questions with any kind of specific information.
1. Engine year, make, type, model, and serial number if possible.
2. Type and model of outdrive, Merc, Volvo, OMC, etc.
There is no such thing as a 3.8 4 cyl. There is a Mercruiser 3.7 4 cylinder, but it normally doesn't have an alternater unless converted, or there is a 3.8 OMC V6.
That is what you should have stated to start with, model numbers work better than just engine size. It's a 3.7L 4 cylinder (aka 470 type engine)All I can find so far for info:Model-MCM 180
Displacement-224 cid
Not hardly, they didn't exist in 87. Not until 88. You have an Alpha IAs for the outdrive,might be a mercury Bravo ?
Any info would be great...(wiring diagrams etc)
I hooked up the battery and the wires,the starter wire from the batt got extremely hot ?