How long should your 40+ year old carburetor last? It's possible that your old original carb has simply worn out. Every time you push the throttle, the throttle shaft wears against the carburetor body creating wear. After years of this, the wear between the shaft and body allows air to slip through the gap, entering the engine. This old carburetor has no way to adjust for this un-metered air, throwing the idle fuel mixture so far out of adjustment that you will never be able to get the car to idle properly once it has warmed up. The only answer? You need to buy a 100% new carb. Even so called rebuilt carbs do not address this problem. We stock a complete selection of Brand new Carburetors.