Briggs and Stratton 7HP Primer Mystery

I have a 7HP mower with a primer bulb. Can not get it to prime. On examination, i've found that the primer in the air box affects one small hole on the back of the air box. That hole does not interact with the carburetor, as it is outside of the carburetor port, and does not connect to anything. Just how is this primer supposed to do anything??

It would be much easier for us to help you if we knew the model, type and code numbers of your engine. We can make some guesses, but that won’t be of much help to you.

John here is a video I made a while back explaining how that set up works .....

https://youtu.be/iuIWIC6NjF8