Doesn't take a tech to answer that one.
As you "unscrew" the upper one it takes up the slack in the cable, that one is go. :lol: The lower one is the whoa return.
There is another adjustment that can be made at the bellcrank near the front of the thottle bodies but that takes a bit more work to do. :cry:
I believe, but don't not quote me on it, the manual says to have about 1/4" slack on both sides, personally I do about 1/8", measured by the grip rotation, on the go side.
If the go side is too tight, it cannot return to idle properly, as in too fast of an idle. If you do not have the whoa side adjusted correctly, it can shut off almost all fuel supply and cause idle stall problems. I generally keep mine slack enough to return the grip to "neutral" idle.
BTW: Cables do stretch with use. :cry: