Would leaving the ignition on cause damage to the coil?

[SteveR.]

I don't think so, as it shouldn't be any different than running the car for an extended period as far as the coil is concerned. I left my ignition on overnight (killed my two-week old 6V Optima), and now the car seems harder starting when warm. Spark is orange, not blue. Swapped condensers, no change. Set point gap and filed the points. Just wondering if it is possible to damage the coil by leaving it on for hours.

Thanks for any input!