2006 Mercury 25 HP EFI 4-Stroke Tachometer Sending Wire Color 2009 Tracker Grizzly

[hattrup1981]

I have a 2006 Mercury 25 HP EFI 4-Stroke outboard on a 2009 1448 Tracker Grizzly. I want to add a tachometer but do not know what color the sending wire is. The motor has a wiring harness that is not being used since I have no gauges on my boat. Does anyone know what color the tach sending wire is? See picture of wiring harness. Anyone know what the other wires are for? Thanks!!!