Throttle cable for 1991 Trail Boss 350 4×4

I have been having issues with the engine not idling right, or even staying running without giving it some throttle.

When I was replacing the head gasket, I noticed the throttle cable is for 2 carbs. The 350 is a single cylinder. I went to the dealer, and it shows that I have the right cable.

Why would there be a wye in the cable that goes nowhere?