wire gauge question

[neal zimmerman <neal.zimmerman@xxxxxxxxx>]

I am working on the cudas wiring this week. at some point the bulkhead
connector melted down, so i found a good one.
  heres the question bear with me.
     Obviouysly the meltdown came from the two heavy leads go to and
from the ammeter.And when i pulled the gauges last nite I also saw
melting  up closer to the ammeter between the two heavy leads, they
were lying next to each other and were starting to  look pretty gooey.
  I am thinbking of replacing the whole circuit, from alternater, up
thru ammeter and out to starter relay with a heavvier gauge wire to
aid in cooling,( via less resistance), but i am wondering if that will
throw out the ammeter, like are they calibrated to that factory size
wire??
  thanks .
  PS anybody care to explain to me what a fusible link does?
  neal zimmerman, eugene oregon