vonguinness,
Welcome to the Stovebolt forum. I think I understand your question...If your '48 still has a 6 volt system, and you installed a 12 volt battery to start it, the starter wouldn't hold it against you. The voltage regulator probably didn't like it, along with the fuel gauge, but, bottom line is, these would not stop the old girl from cranking over after it died.
Several things could be happening. The starter is getting full battery voltage, but is worn out, and can't start the rig a second time..OR, one of your battery cables (or both) are loose, dirty or not tight..OR, the engine has seized somehow.
The system wasn't setup to charge a 12 volt battery, so it was discharging all the while the rig was running. It must have a FULL charge, the cables must be clean and tight and the connections to the starter and frame grounds must be clean and secure.
Do these things first, and more folks will be along with other ideas soon. Good luck.
Stuart
