Reply To: mercury 120hp force straight4 trigger question

[billw]

That’s why Mercury calls it “ADI,” for alternator-driven ignition. The flywheel generates everything it needs for ignition. As for the trigger wires, my Force-speak is a little old but you should find that you have continuity between two pairs of those wires. There are two small coils in the trigger assembly. As the flywheel turns, magnets pass by these coils and generate a small amount of electricity. The direction of the current changes as the magnets approach, then pass, the coils. This change in direction is taken into consideration by the switch box (or power pack, for OMC guys) and allows the switch box to know which coil to fire. The trigger generally only produces a few volts and is usually about the last thing wrong with ADI systems.

Long live American manufacturing!