Because it won't tolerate any extra fuel when it is running, it sounds as if it is rich. Fuel dripping from the air filter sounds like flooding or over-priming. The most common cause of flooding with those diaphragm carburetors is an incorrect lever arm setting. However there is another possibility as well as that: you said you had worked on the primer bulb. If you happened to connect the input and output tubes the wrong way around, you might get a result something like you've described.
