To adjust the kickdown lever, first loosen the lever from the carb linkage and then push it to a full on position, away from the carb. Next, open the carb throttle all the way and rehook up the linkage. If the linkage has a slot in it for a slide adjustment, make sure that when the carb is at full throttle, the kickdown is fully engaged, and when it is at idle, the kickdown linkage should have a relatively mild spring hooked to the front to draw it all the way forward so it is actuated right off idle. The spring usually goes to the same post as the throttle return spring. I might have a picture of mine , if I can find it, I'll post it. A correct operating kickdown linkage is essential for happy transmission operation.