You have a poor connection between the ign2 (crank) terminal on the ign switch and the coil (& maybe the ign1 "run" circuit also which is why when you bypass it with your jumper it starts. start with the bulkhead (a frequent culprit). Might be low voltage AT the ign switch (it has a connector which can be problematic but nothing like the bulkhead). A small metal bristle brush is good for the male ones and a spare male terminal for the female ones (the ones on both halves of the bulkhead). spray clean em when done. NAPA male ones are 725145 if you dont have any spare wiring/terminals laying around-99 cents ea.