I was running a 350 Scrambler without the battery and right off the altenator using an AC coil and phasing the altenator so that the impulse would trigger at the same time the points opened. It worked but I went back to a recifier - battery system for more reliable lighting. I kept the same AC coil on it but am having some starting problems. I re-phased the altenator to original spec. What is the difference between an AC and DC coil? They seem to be simple devices but I don't know if this is causing some of the problem.