Strangest thing...is this right?
 

I was running up my Canadian Mk.1* UC tonight and noticed something I've never noticed before. I turned on the ignition switch and the red dash light went on as is should. Hit the starter, engine fired up and the light goes off as it should. I'm in the back and manually working the throttle only to notice for the first time ever that as the engine accelerated the red lamp stared to glow but very very faintly. The higher the revs the brighter the lamp but even with significant revs it was just barely visible (you wouldn't notice it at all in daylight, perhaps a half volt or so instead of 6). It's all original 6V and wired per the manual.

Is this right?

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???)

No other issues at all. I just replaced the battery and re-did the cable from it to the starter button and the glow could have started after that, however to be honest I doubt I would have noticed it with the old cable/battery (it's that dim) and only did this time because of how dark it was in the garage.