Alternator wire size to small?

[NHolladay]

Alright ladies and gentlemen, I have a 2003 25 LSV 8.1L.  problem is when stereo amps are running and I turn on 2 Johnson reversable pumps I get a low voltage alarm.  When I look at power to alternator it has clearly been very hot  and melted the power cap covering the connection.  When I dig in to the wire it is a tiny 10 gauge wire split to two 8 gauge one to the main engine fuse and one to the starter all factory mind you. Then from the starter to the perko it is  2 gauge wire.  I feel running a new larger gauge wire maybe necessary now that the system has all this draw.  Original plan when I started this was to upgrade to a 140 amp alternator but have serious reservations about that wires ability to deliver power.  I am putting in a brand new 70 amp alternator but want to be sure I do not repeat the same thing, could have caused fire or left me stranded if it went much longer.

 

This will not be easy the wire packs these are run through are not really something I want to be cutting into as the harness was obviously built outside the boat and brought in for connection at an early stage of building the engine.  Would I be ok putting a new tough connection and making sure everything is tight.?.  I thought maybe the heat was caused by a possible loose connection.

 

Please any advise is appreciated

 

 

[MLA]

The look of a hot or melted connection may not be due to an under size wire but can be due to a loose or poor connection. 10ga over a short distance would be normal for a 70A alt. I would replace the entire cable because I doubt you will have enough slack to cut back the old terminal and install a new one and still reach the alt. So take this opportunity to upgrade the gauge. If already buying a new alt, might as well up the amps with the replacement.