Obviously, I have the same problem with my A4 that David experiences. Stalling after 2 miles under motor. Mine is in a Catalina 27 and the tank is installed on about the same level as the carb sits. Checked my fuel pump (mechanical) and it worked fine - at least when operating it with the lever. Since there is no gas smell in the oil I assume the fuel pump to be ok.

In a recent attempt to fix that thing, I took the carb down and cleaned it. I also checked the float. Now that the problem only occurs with a hot engine, it has to be a temperature related issue. The floats may fail when hot due to micro cracks becoming larger under heat.

I also readjusted my idle to 1 1/2 turns. Seems to run smoother now but it did not fix the stalling.

Thank you
Christian