I have a 31 Ford Pick-up all original I am working on the electrical and have a question for someone. on the battery it looks like it may have been positive ground. I have it hooked up as negative ground and it fired on the third time over the amp meter read positive for several weeks until I oiled the generator and the generator sucked all the oil out of the oil pot now it is reading in the middel I think the contact are soaked with oil. 6 volt sys. should I turn it to a positive ground