In my experience there is normally fuel in the primer bulb. Perhaps you have an air bubble temporarily trapped in it - this may cure itself when you've used it a few times. If you make a note or diagram of the way the screwdriver slots in the jet screws are aligned before you clean the carburettor, then clean it fairly gently with a paintbrush, you can check that they haven't moved (which is unlikely to happen anyway). To tell you which of those screws is slow speed and which is high speed, we would have to know what make and model of carburetor it is - and that would be easier to figure out if it were clean.
