Fiat 500 F, Bj.1970 resumes clean gas

My Fiat 500 F, Bj.1970 no longer participated in clean gas. When "rapid" acceleration of the engine often went from easy.
As a problem I had the carburetor suspected since the vehicle has not waited for years by the previous owner. As "emergency aid" I tried Liqui Moly 5100 mtx Carburetor cleaner.
After only two short trips the problem was gone, and the engine now running again perfectly round!