It just needs a ground and 12volts, then you tune the choke by twisting the black spring housing clockwise or counter clockwise. There is also a small screw near the center of the throttle arm that adjusts the fast idle.
You should also say that the choke +12v should NOT come from the coil. It needs to be a real +12 volt, not the 6-9V that the coil sees. It will cause the choke to come off to slowly.
In a jet boat, the added RPM from the choke could be problematic, so proper adjustment is critical. Here a mechanical choke is probably better than an electric as you can adjust the rpm / enrichment on the fly...
