Homelite Model: UT08111 Backpacker

Thought I was finished. I was working on a neighbors blower that had been sitting outdoors for a year or so. Ethanol had melted everything into a plastic puck in the tank. I replaced the filter and lines, air filter, and rebuilt the carburetor. I did not replace the primer check valve or gas cap(both on order).   I got it started, and it ran very strong, and idled well. Only, problem is that it blows air from the fuel filter like an aquarium aerator, pressurizes the tank, and vents fuel from the gas cap. I don't know if this was a prior problem or if it something I injected into the rebuild. Any thoughts? I would be most appreciative.