Runs at FAST idle, not slow

UPDATE: Ok - I got a carb rebuild kit from mike's carbs, did the rebuild and b4 I started the car, I disconected the fuel line from the gas tank, hooked up the fuel to some premium gas, used the cranking of the engine to purge the old fuel from the fuel line, thus ensuring I only had clean gas going into the rebuilt carb. Started it up, and same problem,won't maintain a low(er) idle speed. My son thot the fuel filter might be clogged, even tho I recently change it out, so I bypassed it and no change. Any ideas would be appreciated.