You will not normally have any charging at slow idle with a generator, no matter where the third brush is set. The charging rate should be set at about 12 mph in high gear, not at idle, IIRC. I just have a cheapo tractor six volt in my 33 sedan and have no trouble starting when it sits for a month, though it is best to prime the carb because todays volatile fuels evaporate in the bowl.
