Coils also do get tired over time. They are not big bucks, I replace mine fairly regularly. I encountered somewhere recently (perhaps here, but I think not) that 12 volt systems need a current limiting resister on the low voltage side of the coil, 6 V systems do not. A 6, converted to 12 won't have this resister in place. The coil can get pretty hot if the ignition is left on without the engine running. This will be hard on the coild over time (it could boil out the oil or what ever is inside them). Just a thought
David
