I'm replacing the ammeter on my 40 master85 with a NOS gauge.
Neither the old or new gauge has any sign of the two electrical
posts being insulated. Those posts also serve as mounting studs to mount gauge to the panel back. Seems like current
would just short across the plate between the studs and go on
to the battery without going through the gauge unless the plate
does not conduct. So how does the ammeter work?