Tachometer hook up 1973 65 HP 'rude

[Uniflite32]

I'm trying to hook up a tachometer to my 1973 65 HP Evinrude. There's a gray wire in the control box (not electronic shift) for the sender. I need to know which of the 4 ignition switch wires is the "I". I would prefer to not run wires back to the motor.

 

[rickdb1boat]

Re: Tachometer hook up 1973 65 HP 'rude

Should be the purple...