I do have a nice stream of blue smoke. You mean the idler screw on the carb dont you? If so, I have unscrewed quite a bit right now cause it idles real high if I dont. If I hit the brakes, should the carb on a rotary valve carb should open up on the left of the slide should it not? On top of the slide is where I have the opening when it is at idle. When I hit the brakes it completely shuts this opening.