Normal voltage against a fully charged battery on a "6V" system should be 7.5 volts while running. That will produce a 5-8 amp current going into a good condition 6V battery. Send me a PM and I can detail the proper way to check and adjust a mechanical contact regulator. It's a bit too complex of a procedure to do in an open forum post- - - -a phone call will be a lot more effective. I have a sneaky suspicion that the wiring connections at your ammeter are the cause of the problem.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!