It's pretty basic, there is a nut that holds the coil spring assembly in the choke can, you simply loosen the nut enough to relieve some of the coil spring pressure pushing up the rod, then retighten it. You should have enough pressure on the rod so that it JUUUUST barely closes the butterfly when the engine is cold. You'll probably have to play with it a bit to get it just right. Also, a bit of choke lube (specifically made for chokes) is often helpful to keep everything operating smoothly, NAPA sells it.