I have a 80 truck with a 20r/22r hybrid. When I start it, it revs to about 3500rpms the when it gets warm it goes down to about 2100rpms. I tried adjusting the idle screw and id doesnt do anything, my guess is that either the choke is stuck open or is not adjusted. THis isnt the electric choke but from what the book says it is controlled by water. Does anybody know if you can unhook the choke, and how hard is it to replace the choke. what parts are needed to replace the hole thing, when I look up choke on autozone.com it comes up with a list of parts and I dont want to buy anything that I dont need.