Strangest thing...is this right?

[Lynn Eades]

Bruce, Your ign. warning light is fed from two directions. First you have 6 volts from the battery that lights up the light (key on). Then when the engine is running, you get 6 volts from the generator that opposes the battery voltage. This (equal pressure) puts the light out. It stays out usually, but your genny output might be high enough to make it glow dimly in the dark? Are you having any other issues?
Put a volt meter across the battery when you have been running for a while with a few (say 1000 or plus that) revs and you should be getting about 7.2 volts.

The wattage of the bulb will make a difference to how much the bulb lights up with a small voltage differential. (Have I got that right???)