aaah, good thought Fred .... is this the case FPM? if it's a solenoid start, a 6V solenoid very likely wouldn't appreciate 12V, but you should be able to make a 12V solenoid work
"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