Ok, we tried recharging the magneto in the truck of my TT. We zapped the post as normally described at the north poles (we think; the readings were difficult). We started it up and switched over to mag and the motor goes dead immediately.
So, now what? Yes, first there could be a short somewhere in it, but is it also possible that the post mounted to the hogshead is too worn to make contact? There didn't seem to be any pressure when I put it back in (true, it's a mild spring). The tip is very flattened. Do you think putting in a new post would do anything?
Is there an in-car way to find if there's a short? Electrical is not my thing, so try to explain in simplest terms, please!
Many of the articles written about mag charging in the car actually have the poles reversed and you end up charging the magnets in the incorrect direction which usually results in a mag that seems to be charged okay, but that looses its charge very quickly... Sometimes this "discharge" is a matter of hours, or a matter of days. Try re-charging opposite of how you did it last time and see what happens...
We ran into the issue of wrong diagrams on this forum. We used 3 12 volt batteries in series to zap it. The positive cable was attached to the magento post and we left the negative cable unhooked. We then hit the ground cable of the TT with the negative to zap the post.
As a note, a good, 100% correct way to recharge the mag in-car using 12 volt batteries would be a great "sticky" to keep as a permanent post. I would also put up a list of all the incorrect diagrams to avoid. Thanks!
I am definitely not an electrical guru and hope that others will help out, but you may have worn Babbitt on your main cap allowing too large of a gap between the magnets and ring.
(I tend to think mechanically because I understand electrics as much as I do women.)
If an in-car recharge that has been properly performed does nothing, here are most of the likely issues:
excessive end play
shorted/grounded field coil
open field coil
bad mag post
one or more cracked magnets
no field coil in the engine (don't laugh; it's happened)
A good way to narrow the problem would be to check voltage output at the mag post with an antilog volt meter. If you have good voltage there, then the problem is outside and if you have low or no voltage the problem is inside. This will let you know where to look for the problem.
Here's how Ford recommended it be done. You should point the car east or west so you can observe the compass move to north when the magnets align properly:
The post normally protrudes about 1/4" with the screws loose due to the spring on the post. It sounds like the post might be at fault.
Was this way of charging ever a 'FORD' publication?
The service bulletins actually condemn the practice of in car charging in 1924.
Not until October 1926 before getting a write up on doing in car charging with a KRW charger.
Ford said their "preferred" method was to remove the magnets from the car for recharging, but did say you could do it in the car in a pinch.
Review this recent thread on this subject. It explains better what is going on, and offers several ways to achieve the desired result.