78 Ski Nautique shoots gas out the vent of carb

I have a 78 Ski Nautique. Ran fine last year when I put it away. Went to start it this year and the water pump was leaking and the vent in the carburetor was shooting fuel straight up. Replaced the water pump. Tried tapping on the carb with a rubber mallet in case the float was stuck. Didn't help, rebuilt the carb and put it back on, same problem, rebuilt it again just to make sure, same problem, put different floats in, same problem. The floats seem to be working correctly because when you pull the screws on the side the fuel is at the correct level. Finally ordered a brand new carb and put it on. Exact same problem. No idea what to do next? Engine is Ford PRD WR R10 and Carb is a 4 barrel Holley.

Doesn't the clear fuel pump bypass line run to the spark arrestor on top of the carb, so when the fuel pump diaphragm fails it pumps fuel into the carburetor and stalls out the boat. I think it's a safety feature so the pump doesn't dump fuel into the bilge.

Sounds like you have a different issue, but thought i would mention this just in case, since it would also put fuel into the carb in a weird location.