Ferrari 330 GTS

We sold this 1967 Ferrari 330 GTS a year ago and much to our embarrassment, the car never ran properly for the new owner. It would run out of power at low speed and run poorly at idle. It seemed to behave at speed but who cares when every other area it seemed to misfire. Even though we overhauled the engine less than 500 miles ago, it never performed well for the new owner.

What we found was that one of the Weber DFI carburetors had a casting flaw that allowed fuel to leak from the float chamber to the intake stream UNDER the throttle plate. You would look into the venturi as the engine ran and witness no fuel dripping as we often do when an accelerator pump diaphragm leaks or a float level is set too high but we couldn't see any dripping.

It was not until seeing some excessive steam/smoke coming from the carburetor choke fueling cylinders 9-10 that I pulled the carburetor.

Fuel was indeed leaking under the throttle plate through the idle air bleed screw.
Now the engine runs perfectly and the car is off again to the new owner!