Chumley

Please enlighten me on this part( idle-stop solenoid) . Is the purpose to close the throttle completely on ignition shutoff to prevent run-on? The engine in my '72 is actually a '73, and has the solenoid. I installed a new engine wiring harness ('72) that has the same connection as the old '73 harness. I just installed a '72 carb that is essentially identical to the '73. Haven't fired it up and tuned it yet, but am wondering if I should hook up the solenoid. Thanks, Chumley