Mercury - Tachometer Harness Engine Gauge Wiring Black Face Chrome Bezel 84-46239A1. OverviewThis tachometer harness connects your tach to older three-blade style Mercury control setups. It's a straightforward plug-in lead that works with classic 61490A-series controls and the older ignition/choke panels. Out on the water, it keeps the tach signal clean so the gauge reads the way it should. Nothing fancy-just a solid, dependable harness for older rigs.. Key Features • Three-Blade Connector - Mat