Connect a heavy wire, or maybe a jumper cable, from the starter to the ammeter. Install the battery cable and stand back. When the smoke clears, the shorted circuit will be very obvious. Suggestion- - - -have a good fire extinguisher handy! Otherwise, use a little logic and common sense and find out where the incorrectly connected circuit is. Quit obsessing about the generator- - - -it ain't the problem if the regulator cutout relay points aren't welded together.
Jerry