Verify that the cap on the fuel tank is secure before attempting to take the head off the Ryobi EZ Start 40:1 weed-eater.
Turn the weed-eater upside-down so you are looking at the bottom of the brushcutter guard where the head sits.
Turn the retaining spool counterclockwise to remove the head from the threaded bolt on the end of the Ryobi weed-eater.