Oil Gauge Wiring Question Re: The Ignition Wire

[1985 Century Mustang]

My boat came with just an oil light, I want to install a gauge now. I understand all the wiring except for the ignition wire, my question is can I run a wire directly to the actual starter, or do I have to run it to the actual ignition wire. If so does anyone know which color wire is the ignition wire on a 1985 Merc Alpha One Gen One.

 

[Scott Danforth]

Wire the gauge to the other gauges. Just daisy chain the +VDC (purple wire), the ground (black wire) and the dash light (blue wire). The sender is the light blue wire under the dash