The Carter B&B (Ball & Ball) carburetor is an older style carburetor that was used on many vehicles and engines from the 1930s through the 1960s. Flooding, or the over-supply of fuel into the engine, is a common problem with many carbureted systems.

Here are some reasons why a Carter B&B carburetor might flood:

1. Faulty Float: The float in the carburetor bowl can become damaged, saturated with fuel, or misaligned. If the float doesn't rise with the fuel level, it won't shut off the fuel flow, leading to flooding.
2. Damaged or Dirty Needle and Seat: The needle valve, controlled by the float, seals against a seat to regulate fuel flow into the bowl. If the needle or seat is damaged, dirty, or has debris caught in it, it might not seal properly.
3. Incorrect Float Level: If the float level is set too high, the carburetor can flood. Adjusting it to the correct specification is crucial.
4. Blocked Vent: The carburetor bowl is vented to maintain atmospheric pressure inside. If the vent is blocked or clogged, it can cause an imbalance in pressure, leading to flooding.
5. Excessive Fuel Pressure: If the fuel pump is delivering too much pressure, it can overcome the needle and seat's ability to stop the flow of fuel, leading to flooding.
6. Choke Malfunction: If the choke system is not operating properly and remains closed when it shouldn't be, it can cause the engine to run overly rich and appear as though it's flooding.
7. Old or Contaminated Fuel: Old gasoline can lead to varnish and gum deposits which can cause various problems, including potential flooding conditions.
8. Heat Soak: After shutting off the engine, heat from the manifold can "boil" fuel in the carburetor, causing it to flood. This is especially common in older vehicles with inadequate heat shielding.

To resolve flooding issues in a Carter B&B carburetor:

1. Inspect and Clean: Dismantle the carburetor and thoroughly clean all its components. Pay special attention to the needle and seat, ensuring they are free from debris and in good condition.
2. Float Adjustment: Check the float level and adjust it according to the manufacturer's specifications.
3. Replace Damaged Parts: Replace any worn, damaged, or non-functioning parts like the float, needle, or seat.
4. Fuel Pressure: Ensure the fuel pump is delivering the correct pressure. You might need to install a pressure regulator if the pressure is consistently too high. 3.5-4 lbs.
5. Choke Adjustment: Ensure the choke operates and adjusts properly.
6. Fuel Quality: Empty old or contaminated fuel and replace it with fresh gasoline.
7. Heat Shielding: If heat soak is suspected, consider installing heat shielding or spacers to prevent excess heat transfer to the carburetor.
8. Inspect Venting: Ensure that the carburetor bowl vent is clear and free-flowing.

If the problem persists after troubleshooting, it may be helpful to consult with an experienced mechanic or someone familiar with Carter B&B carburetors.