How to keep fuel up to the curb after shut off.

I'm no expert but I'm wondering if you've got another problem. It's abnormal to experience a lack of fuel at the carb on each startup. I've heard of carbs that aren't vented properly siphoning gas into the intake after a warm engine is shut off.

If it's really returning to the tank I would wonder about the condition of your fuel pump and whether or not your tank is vented adequately.