The mag is equipped with an impulse coupling. This device is a spring loaded trigger operated mag component that speeds up the mag internal magnet. At cranking speeds the magnet turns so slowly that the voltage it produces in the coil is not sufficient to make reliable spark. The mechanism locks at each cylinder location and as the engine turns, it winds the spring. when the engine gets to TDC, it triggers the release of the spring, allowing the magnet to leap faster for a fraction of a second. this makes nice fat spark. When it sparks the tractor starts, and the impulse system is disengaged the running tractor has all the speed it needs to make spark level voltage in the coil. It also advances the spark to full advance for running and work. It is set at TDC for the impulse to prevent backfiring and kickback when cranking manually or with a starter.
To fix yours, the impulse coupling needs to be cleaned out and lubed with a PTFE spray like Tri Flow. Set the #1 piston at TDC on the timing mark, with the mag rotor pointing to (or near the #1 plug wire terminal on the cap. If you carefully remove the mag, and do not move the engine, putting it back in is not an issue, if it ends up pointing at the same location. Be careful with internal parts, there is internal timing marks on the rotor shaft as well. Best of luck. Jim
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Today's Featured Article - The Fordson F Ignition System - by Anthony West. A fellow restorer contacted me earlier this year asking for some help and advice on a model F that he was restoring. He had over a period of months spent a fair amount of his hard earned cash on replacement parts for the old "trembler" ignition. Sadly though all his efforts seemed to be a waste of time and money as he still couldn''t get the temperamental old thing to run correctly!! If i said that this was a little frustrating for him that would be "conservative" in fact the problem had reduce
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