1991 Chevy Silverado Won't stsrt

Truck wouldn't start one day, rolled over & if I put fuel in carb, it would burn that & stop. I tapped fuel tank w/ rubber mallot and it fired right up. Was ok for 2 weeks until I had to pull the trusty mallot from behind the seat, started right up again but later that day, I had to leave it parked over night at a store. Next day, I replaced fuel pump in tank and thought I
had it fixed until 4 days later, won't start again. I pulled off the filter in front of the tank, and when the key is turned on, gas pours out. I replaced the filter with a new one. Still won't start. I pulled fuel line from carb and rolled engine, Shouldn't fuel be coming out of line? I got nothing.