Your going down the wrong path, remove the front and back carbs and rest the idle mixture screws in the bases of them so ther both set at 1/4 to 1/2 turn out from bnottomed out, DON'T screw them in to tight Put them back on and readjust the center carb as needed, first thing is back the idle speed screw down so the throttle blades on the center carb so they are almost closed completely Let us know how that works BTW,once you get them to idle get ready to work on the outboard vacume pod springs Six paks are fun, huh You can do this