if it still has a 6V starter, on 12V, you may have fried the starter by cranking it long enough to overheat it .... first check all connections carefully, might have overheated a cable first
"When we tug a single thing in nature, we find it attached to the rest of the world" ~ John Muir "When we tug a single thing on an old truck, we find it falls off" ~ me Some TF series details & TF heater pics