Walbro Wt-603 New carb Problems

No you don't get gas through the pulse port. It only get pulses of air and that is what makes the fuel pump in the carb work. Since the bulb is on top of the carb it may only fill like half way. I still think that having the return line at the bottom of the tank maybe causing the problem or the carb has something inside thats plugging up the port that goes into the cylinder.

Ok, So the bulb has never had any fuel go into it, The pulse port is only for air... I happen to have a Cat eye gas tank, on another homemade bike, A buddy of myne had a frame with wheels and brakes, we bought a 47cc water pump motor and used the old clutch assembly that was on the bike, I can take that off and temp hook it up and see if it solves the problem, and if it does then I'll know for sure that it's the fuel return line causing problems.
Also if the pulse port isn't responsible for getting fuel into the bike then where is fuel sent in?

You can check it by putting a kink in the return line and pull it from the carb than put another return line going to your gas can. Than if that isn't it take the carb apart and clean it out and make sure nothing is in it that is blocking it up. The pulse ports air pulse is what makes the fuel pump in the carb push gas in to the motor. Are you sure the pulse port you drilled didn't get covered up by the case when you put the intake back on?

Ill do this all and let you know, Thanks for your continued support!