If you hit the switch, the starter will spin anytime.

With your switch in the On position for exended periods, most of your iginition system takes a beating. Points, cond, and maybe the coil will all be toast.

If the wires are original, they are probably in pretty tough shape. My wiring system is all factory and in need of replacement. If some P/O decided to rewire or repair, I would hack out the repairs and buy a new harness. A new elec system is pretty cheap.