If you look at the link that the choke pull off pulls against to open the choke you will see a big U in it. If you spread the U apart it will shorten the amount it opens the choke plate. If you take the vacuum hose off the pull off and move it by hand you will be able to tell how much its opening the plate. This should get you close without having to start the truck. Once you get the pull off adjusted then you can move on to other adjustments. Good Luck Don