How do I remove the gas tank to replace broken fuel return line?

You don't really need to remove the tank to replace the fuel line but it is difficult to get at the small fuel lines. You do need to remove the green plastic housing which is held with 2-3 screws. Take the old line to a lawn mower shop and get the exact matching line and replace the clunker. The clunker is a filter and weight to keep the intake below the fuel level in all positions.