This page details the float weights of the three original style B-9550 Model B Zenith carburetor floats.
The 1932 Model B first used a cylindrical barrel shaped float, then a rounded shaped float, and later used a rectangular shaped float in 1934 and beyond. The rectangular float style is the most commonly found.
Each of these float styles use different upper castings with different float hinge pivot brackets.
The pic above somewhat shows the relative differences between the early cylindrical barrel float on the left, the subsequent lighter rounded float in the middle, and the final rectangular float on the right.
Discrepancies in proper float weight may lead to valve seating issues due to the inverted needle valve. This could then affect fuel level in the bowl and fuel consumption and carburetor performance.
Shown in the table below are the results of measurements using a digital gram scale on a sample of original B-9550 floats, including NOS and unmolested used floats in my collection.
| Model B Zenith Cylindrical Float B-9950-A |
Mass (grams) |
|---|---|
| Cylindrical used | 25.9 |
| Cylindrical used | 26.4 |
| Model B Zenith Rounded Float B-9950-A |
Mass (grams) |
|---|---|
| Rounded used | 18.3 |
| Rounded used | 18.5 |
| Rounded used | 18.8 |
| Model B Zenith Rectangular Float B-9550-B |
Mass (grams) |
|---|---|
| Rectangular NOS | 13.4 |
| Rectangular used | 13.6 |
| Rectangular used | 13.6 |
| Rectangular NOS | 13.8 |
| Rectangular used | 14.0 |
| Rectangular used | 14.0 |
| Rectangular used | 14.1 |
| Rectangular used | 14.2 |
| Rectangular used | 14.6 |