Set the choke with a cold engine, turn the bimetalic spring housing until the choke plate is approx open 1/8th of an inch. A quick test is, lightly touch the back of the choke plate to see how far it will open. The reason is, the choke pivot shaft is offset, you should see that the back half of the choke plate is larger. The incoming air will assist the opening of the choke, the bimetalic spring won't open it, itself. The choke only opens when the spring relaxes, (as it's being heated) and the incoming air does the rest. If you get it right the first time, you'll be the only guy in history to do so. This is going to be a starting point, your going to have to play with it a bit. As the weather changes, (temp) you'll have to readjust the spring tension. One notch maximum at a time. Ok, now you have the choke adjusted, but your finding you only get about 3 or 4 blocks from your home and the the engine is wheezing and coughing and barfing black smoke. Things are a tad rich. Take a look under the housing, there should be a green colored screw. It's hard to see, it's way back under there. Philips head if I remember right, turned in, it should shorten the time the choke is applied. Turned out, it should lengthen the time it stays on. Half turn maximum at a time. Giver a try.