Sometimes they kick back and sometimes not at all. If it kicks back and tries to take the rope from your hand, you can almost be assured it's the key.

Did you purge the gas line by draining some gas from the bottom of the carb?

If you have been pulling and pulling on the starter it might be very well flooded. Pull the plug and if it's wet pull it through a few times and leave the plug out for a while to dry things out.

When Bail is pulled back,Check that the stop switch is open.The cable does stretch after a while.