Hi All!I have a 1951 Allis Chalmers type B with which I have had a very puzzling electrical problem. I'm posting to the Ford N Forum because the real electricity experts seem to hang out here. This problem is so unusual, that even if it doesn't get solved, its worth adding to the knowledge bank at these archives. For the record, the tractor is a converted 12 volt system, alternator, ballast resistor and 6 volt coil. The tractor was recently running really weak, then quit all together. I started tracing the problem back through the electrical system. No matter what I tried, I could not start the thing. I only suceeded in running the battery down from working the starter. Somewhere during the diagnosis, I carefully pulled the cable off the coil to ensure I was getting a good, solid spark between the coil and the plug cord. I engaged the starter and saw strong, inch-long sparks coming off the center lug of the coil - then suddenly, the tractor unexpectedly puffed to life! As long as I held the wire about an inch off of the coil, the tractor ran great! Too far away, and the spark couldn't junp the gap so the tractor died. Too close or touching the coil - the tractor starts to gag, miss, hesitate, blat and finally quit. That's right - the tractor runs BETTER with the cord removed from the coil, not when it is attached to the coil. Weird huh? Well, this afternoon I tried to solve this problem using several different approaches - but none seemed to solve the problem. I tried my 6V coil with an external ballast resistor, I bought a new 12V coil with internal resistor, I traded out the condensor with the spare I keep on the shelf. I increased the point gap from 0.020 to 0.022. I even spoke sweet nothings into its distributor cap. In EVERY case, I could get the tractor running only when the coil plug wire is removed from the coil and the spark is forced to jump across the one-inch gap. I even showed my wife so I'd have a witness to this oddity. I'm stumped. Once started and hot, it is possible to replace the wire into the coil and keep the tractor going, but it hesitates, misses, blats, coughs, and runs really rough. By throttling up and easing it into gear,I was able to move it closer to the house to work on it further this Saturday. But it is currently in no condition to mow the yard. Anyone else here had this problem? What could possibly cause this problem that I haven't already replaced? I am guessing its a timing thing. That's all that's left to change (and I tried that already too).
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