I have a long duration, high lift camshaft. There's so much fuel in the exhaust it will burn your eyes at idle. Is something wrong with my Holley carburetor?
The most common cause is an improperly rated power valve. A camshaft of this configuration requires more air and fuel for it to operate efficiently. This in turn requires adjusting the curb idle screw to obtain the same idle rpm that you had with the stock camshaft. If you are having a problem with the air/fuel mixture screws not making a difference, the curb idle screw has probably been turned in too far. This causes the throttle plates to open too far and uncover the idle slots, allowing fuel to bypass the idle circuit and start pulling from the transfer slot. To correct this problem, raise the secondary throttle plates a little with the secondary adjusting screw. This provides more airflow into the engine and will allow you to lower the primary throttle plates. Another method would be to drill a 1/64" to 1/8" hole in each of the primary throttle plates on the side closest to the transfer slot. This will allow extra airflow into the carburetor and also allow you to lower the primary throttle plates.