I have a craftsman 5.5 mower and it will not keep running. I have changed the spark plug, taken the carb. Off and cleaned it making sure all ports are clear, changed the gas, etc. If I poor gas in the cylinder it will start but will not keep running. There is only one adjustment on the carb. And I have tried everything. Can you help?

You didn't mention specifically the air filter. Also, if you changed gas by removing gas that was in over winter, it may have left a "varnish" on some valves. Maybe some starter fluid would keep it running lond enough to burn off some of the resdiue if the old gas was left for an extended period. But the air filter is critical. I am no expert, just speaking from expeience with my craftsman mowers. Also, any debris wound around blade shaft?
Good luck.

Did you check the fuel line? Does fuel run freely through the line?