I have a 2001 Optimax 225hp that is Smartcraft Compatible. Currently I have all analog gauges and I would like to switch to an older set of Smartcraft SmartTach and SmartSpeedo Gauges. Right now I have both gauges but only have the harness for the Tachometer.

Here is the back of my tach:

Here is the whole set up with harness, tach, harness adapter, and terminal block:

From what I understand, the red goes to a constant 12 V, the purple connector goes to the tach, the other end of the harness goes to the adapter and the adapter leads get connected to the terminal block along with there corresponding wires from the main engine harness.

Here is the harness and harness adapter:
My question here is, the tan/blue wire is in the main harness but not in the harness adapter. At the other end the tan blue wire is just stubbed out as shown:
Its almost as if it just dead ends???

As far as under the cowl connections.......

Do I hook the wires from the this main engine harness to the terminal block?


It looks like I have two gray tach wires under the cowl. One is capped off while the other is connected to another gray wire. Why is this? Is one for digital readout and one for analog?

The one gray wire that is capped off is in a loom with a brown wire with white stripe (trim?). This is plugged into a connector that has a blue and white wire coming out the other side. What is the blue and white wire and why is the brown w/ white stripe wire connected while the gray one is not?

Lastly, I have a capped off purple wire. What is it there for?

I do have a purple smartcraft 5 pin connector under the cowl. Is this not used for the SmartTach?

Sorry for the long post. All help is appreciated. Thanks guys!