Carb idles high, need help...

[Dirtman29]

Motorcraft 2100 carb 350 cfm, brass float, 57 jets, mixture screws 2 turns out, on a mild built 2.3L.
Last year car wouldnt idle at all, now its stuck at 15-1800 cold, once i race its stuck at about 2500 RPMs. Idle set screw isnt even close to touching, linkage is not bound up, have 2 return springs on it. I made NO changes to the carb from last season. It is on a fresh rebuilt engine. Any help greatly appreciated.

[r3tracing]

Look down inside carb and make sure throttle plates are closed all the way. If they are there is a vacuum leak somewhere.

[Dirtman29]

Thanks for the reply, I use a fel-pro 1904 base gasket, wondering if the gasket is holding the plates open. If i manually pull back on the linkage it will idle down. I ran it with linkage off the carb and was still idling high. May have to trim the gasket.

[Foghorn]

Sounds simple enough. Take the carb off, turn it upside down and place the gasket on the baseplate, then open the throttle and see if it hangs up. If that looks good then do as already suggested and check for a vacuum leak. Make sure the carb gasket is fitting properly and if that looks good then check the intake gasket between the head and intake.

[Dirtman29]

I trimmed the gasket, my intake has a single large oval opening and the gasket had the 2 round openings so I just cut the center out of the gasket. Seemed to help as idle is down to 1000-1200 range. Thanks for the replies.