Need some Mercury Mystique wiring help

[Trmin8r]

I was going to put a new alternator in my Moms Mystique today, but saw that the wire going from the alt to the dist block to the battery was missing the insulation. I am hoping that this is the only problem, and all I have to do is replace the wire. My question about the wire is this: Is there anything in that distribution box (underneath the coil pack) that I can screw up? I was going to open it up and replace the wire with a new 4 ga wire.

Also, is the alternator shot becuase of the wire?

Thanks for any input.....