Outdoor Power Equipment and Small Engines - Primer Bulb Leaking

I have a Briggs and Stratton 5.75hp quantum engine, but when I fill the tank, gas starts leaking out the hole in the Primer Bulb.

After taking things apart, it wasn't clear where the one-way value was for the primer. Is it accessible at all?

Thanks for any tips.

Engine model and type numbers would help, but you should have a bowl-type carburetor, which has no such valve. The trouble you have is that the bowl is over-filling and making it's way to the primer bulb. Two possible culprits: 1- sediment or varnish build-up in the fuel bowl is not allowing the inlet needle and seat to function properly. 2- Least likely scenario is that the float has sprung a hole and is no longer floating. Either way you need to service the carburetor by removing it or at least remove the bowl and look for any sediment and blow the bowl as well as the carburetor itself out with compressed air.

How'd you make out?