The dynamo was charging well,but the igntion lamp was out . I put in a new bulb and it works. however when I rev the enGine it goes out but I can just see a tiny tiny glow on the filament. A friend of mine says there should a thin wire winding round the body. mine's missing. two questions; Does it matter if the bulb does what is doing now? and what is the fine wire doing? if I had it!

If you have a look here, I think it may answer your question.


http://www.austinsevenownersclub.com/forum/viewtopic.php?t=744

It wasn't hard to find, I googled "austin 7"+electrics and it was about the third hit.

Regards, Stuart

Hello Derek,

I am sorry that I have no idea exactly what sort of Austin Seven you are dealing with, but can confirm tha some used a resistance around the bulb holder, some didn't.

The lamp should self extinguish once you reach "charging" engine speed (once the cut-out operates). If yours is remaining on, even if it is just a slight glow then something is amiss.

The Lamp is effectively wired across the cut-out contacts and oce the cut-out contacts are closed, the lamp should be totally extinguished, as it is short circuited by the cut-out contacts.

Maybe you should make certain that the contacts are clean, and that the contacts are so adjusted that there is some "follow" on them. That is to say that they should not just "kiss" together, but really make positively and, dependent upon the actual contact arrangement, you should be able to see a slight follow through movement of the contacts together. It is hard to describe but I think you will get the picture.

Take it easy when you clean the contacts, maybe very fine wet and dry paper, and then a clean away of any debris left behind.

Good Luck

Barry R.

Hi Derek, my austin has been doing that for years!
If the dynamo is charging, leave well alone.