Sounds like the carb accelerator pump as mentioned plus an internal leak. I have put in a new fuel pump and still don't have a full fuel filter. It has less than 300 miles on it. Done this before and rarely had a full fuel filter. I think 48bigtrucks and carbking are right. My carb drains out at night somewhere and am not able to find where just yet. Its been rebuilt. I started 41 years ago rebuilding carbs and turning wrenches. Have to crank it to fill the bowl then it takes off. Irritating! I wish you well.
