A "carb fart" is a spit back through the intake. That is a sign of a lean mixture which can be due low fuel pressure or an intake air leak.
Low fuel pressure does not have to be a fuel pump issue. It could be the fuel system has an anti-drain back valve which if is the case could be letting fuel pressure and fuel drain out of the fuel lines.
If you turn on the key and let the fuel pump run a bit before you attempt to start the engine does the engine start better?
But before I went much further with the above possibility there is the good old last thing touched first thing suspected. You might have introduced an air leak.
Low fuel pressure does not have to be a fuel pump issue. It could be the fuel system has an anti-drain back valve which if is the case could be letting fuel pressure and fuel drain out of the fuel lines.
If you turn on the key and let the fuel pump run a bit before you attempt to start the engine does the engine start better?
But before I went much further with the above possibility there is the good old last thing touched first thing suspected. You might have introduced an air leak.