25 hp Mariner tach hookup

[regency01]

I purchased a new tach from a E-bay seller. It has settings on the back for 1,2,3,4,6,8 cylinder engines. Where do I hook up the sensor wire 'S' on the Mariner 25 hp 1988 motor. See pics.






Moved from: Electrics, Electronics and Trolling Motors (not engine)