Several things cause a carburetor to leak gas. A loose fuel line connection is easy to correct by tightening the connection at the carburetor. If the leak persists, the connection fitting is probably bad and it may be time to replace the fuel line. Another cause of a gas leak is a sticking float inside the carburetor bowl. This forces gas out of the sides of the bowl. If gasoline is dripping in the throat of the carburetor, the problem is most likely a ball check valve inside the carburetor body. In most cases, rebuilding the carburetor can repair a carburetor leaking gas.
Obtain the correct rebuild kit for your carburetor. Refer to the model and year of the car when selecting the kit. Some carburetors have a metal tag with the carburetor model number. These numbers help to obtain a kit with the correct gaskets and components.