88bluchevy

The other day went to crank my truck up and it crunk up for about 20-30 seconds then died. Tried to restart but wouldnt restart. Went and bought new pump relay still same thing. Fuel filter is about 4 months old and fuel is about 11-15 yrs old. Took fuel apart from carburetor and switched key on and fuel poured out but was only enough to prime the motor and get it started. After that fuel is burned out the truck dies instantly. I can switch the key off and crank it back up but it only lasts for about 20-30 seconds. Just wondering if its the fuel pump since its getting fuel to begin with then stops.