The Buckshot Racing #77 sixteen (16) foot Mercury 8-pin boat side wiring harness is the control harness that provides wiring from your outboard motor to your driver's cockpit/console. 
 
It contains the pin connector to connect to your powerhead harness including the wires for the tilt/trim switches, key switch power, gauges, alarms, ignition, start, prime, temp, and tach. 
 
The console side has wire ends to connect to any compatible key switch (also available on this site) and a set of panel/dash switches.
 
The motor side has the traditional Mercury 8-pin plug to connect the 1 through 8 colored wires to operate your motor.
 
This harness replaces the old factory harness and it is applicable to drag race boats, tunnel boats, runabout, ski, fishing, and bass boats.