SS BLK SYS. CHECK OMC

Tachometers work by counting pulses generated by the ignition system alternator tach signal generator or magnetic pickup sender. The tach is hooked up to +12vDC Ground. By selecting the right tach and setting the switch on the back to the correct position you let the tachometer know how many pulses are sent per each engine revolution. These tachometers have a warning light system built into the dial that show off warning indicators when a fault is detected from the engine.