Low idle when Hot - First thing to do is set the timing to spot-on, and then make sure there are no leaks in the vacuum line from the carb to the distributor. Fussing all you want with the carb won't make things right if the fire isn't proper. Once the electricals (timing, advance) are in good shape, you can set all the carb adjustments. Simply go thru the overhaul instructions in the shop manual and set all the adjustments as described and you should find it will do fine. Of course you will need to clean it thoroughly and replace the step-up rods if they are worn. And replace any missing mechanical pieces. The idle cam and choke settings have to be adjusted correctly, as well as the idle mixture screws. Furthermore the carb needs to be in good enough mechanical shape that you do not have a lot of extra slop in the throttle shaft for the primaries (the secondary shaft rarely gets enough use to wear significantly). Float level, float drop, throttle plate idle clearance, etc. adjustments are all covered in the manual. That Carter AFB is a pretty straightforward carb, easy to clean and adjust. About the only critical tip might be to insert the step up rods after the top cover is on the carb. This will take a bit of fussing. Do not attempt to install the carb top with the step-up rods already in it as you will almost assuredly bend the rods. Unless the primary throttle shaft is worn excessively you should not remove the throttle plates, it's not really necessary for a good cleaning. It is possible you are getting a bit of fuel boil over, and setting the floats and idle to spot-on can frequently prevent this. You are right there is a thermostatic vapor relief on that carb, when working you can sometimes here a slight whistling from it when it opens. randee jan 2002