Model A

Ford Garage

Zenith Carburetor

A-9545 Secondary Well Variations

The illustration below is from the June 1930 Canadian Service Bulletins, and shows the design change progression of the Model A Zenith carburetor A-9545 secondary well. This is the gas well in the lower casting into which the idle jet siphon tube is suspended.

Changes were made to the secondary well to improve fuel flow around the outside of the well from the float bowl compensator jet and into the cap jet.

The clearance groove in the outside of the secondary well was moved upward to better align with the drilled passageways in the iron casting and to prevent contact to the compensator jet.

Style 1 is the original design with the groove towards the bottom.
Style 2 is an intermediate design showing the addition of an upper groove to Style 1.
Style 3 is the final design, having the groove moved to the upper position for improved gas flow from the bowl to the cap jet.

These changes improved fuel flow from the float bowl through the compensator jet, around the outside of the well, and subsequently into the cap jet.

It is recommended to only use a Style 2 or Style 3 secondary well in your Zenith carburetor.

More related information on Ford Garage:

  1. For more Model A & B related information, use the Site Search box at the top or bottom of this page.
  2. Model A Zenith Carburetor Theory of Operation
  3. Model A Zenith Carburetor Numbering
  4. Model A & B Carburetor Jet Sizes & Flow Rates
  5. Model A Carburetor Float Weights
  6. Model A Zenith Carburetor GAV Wrench

July 2012