Beware of poor quality castings on Quickfuel carbs

[venum14]

Like Blykins stated, manufacturing defects will occur and hopefully they will be addressed with great customer service. If ‘porosity’ is the root cause of your problem or ‘leak’ issue I can shed some light on the topic since it is not understood by the average consumer:

For many years, I have been working in the OEM die cast component and tooling (molds) that produce complex parts. All our die cast/machined components must meet NADCA “pressure tight” requirements so they don’t produce fuel or vacuum leaks (both internal and external).

With this said, all die castings will have some level of porosity/voids. Both die cast and plastic injection tool designs are fine tuned with mold flow analysis software that points to potential trouble areas. Part wall thickness, radii, gating, venting, cooling, and many other factors can reduce or move the porosity to less critical areas of the part. Also, when any machining is performed on the die cast part, the cast “skin” is removed and this opens up porosity that lies under the surface.

At the end of the day, a percentage of die cast parts will leak fuel or air. For critical parts, typically, a pressure decay test (100% of the parts in our case) is performed on the machined part to determine the leak rate. If it falls below a determined maximum leak rate, the parts can used as is. If the leak rate is too high but below a maximum rate (too large of voids) the part is impregnated. The impregnation process uses a ‘sealer’ through a thermal or vacuum method that will fill the porosity voids in the die casting. Now you have a ‘pressure tight’ die cast part.

Hopefully, your parts can be returned and the manufacturer should take the leak seriously. Nobone wants a potential fire from a gasoline leak that could be traced to a manufacturing defect.