I am helping out some friends repair their '41 (possibly '42) 9N and am having lots of problems with the ignition and getting spark. This is a 6V positive ground system still. The motor will turn over, but no spark at the plugs at all. So far I have replaced the coil, condenser, plugs, spark plug wires, distributor cap and the battery. I did find out that someone before me tried to jump the dead battery with a newer 12v system. Is there a fuse or something that I am missing, or something in the distributor that would need adjusting and/or replacement? I am told that before the battery went dead, it was a very strong running motor. Thanks!