I bet your new fuel pump will fix the problem.
I had a Merc electric fuel pump that was over pressuring the float and flooding the carb just like you have. Re-built the carb (twice, thinking I did something wrong the first time), still same problem. Measured pressure and found the pump was putting out over 40PSI. Added a fuel pressure regulator between the filter and carb, and dialed down the pressure. Worked for a short while, but then the pump completely died, no output. For some reason these pumps must over-pressure when they are about to die.
2003 3300 SE