[mr0077]

Put the secondary idle stop back where it was (just crack them open if you don't have the spec), disconnect the linkage from both carbs and crank the idle screws in a half turn past initial contact...start it and adjust the idle to 750-800 or where you like it (if you have a choke make sure isn't acting on a throttle cam). Turn it off and set the linkage so it doesn't move the throttle arms when installed, should be a nice slip fit (make sure the choke doesn't hold things open as it cools). It sounds like linkage problems...post a photo of the linkage if you can.