Engine carburetor leaking into air filter??

Hope someone can help me with this. I own a Snapper 5.5hp push mower, with B&S engine. I believe it was new in the mid-90's. Last summer I had issues with the engine dying on me. My father-in-law asked if there was a hole in the primer (which there was), and suggested sealing it with some silicone. I did it and it worked... for a while. Several weeks later, I noticed gas leaking from the carburetor into the air filter housing and saturating the filter. I was told the float assembly needle and seat probably needed replaced, which I did. It still leaked gas. So I replaced all the gaskets on the carburetor, which seemed to do the trick. In the process of redoing the carb., I also replaced the Primer bulb with a new one. So now with everything cleaned and replaced, I finally got the engine started back up... for a few seconds. Then it died again. Much as it did before I put silicone over the primer bulb hole last summer. So my question is, should I put silicone over the primer bulb again?? Will this hurt the carburetor?? any other solutions or thoughts?