My Featherlite Weedeater Blower 'chatters' more and more, losing power. I removed the bottom blower cover and discovered that the blower fan was hitting the bottom plastic cover below the motor, but when I tried to remove the blower fan, the fan slips on the shaft and won't allow loosening of the nut that holds the fan on the shaft. I wonder if the bearing has failed, allowing the fan to have too much play and therefore hitting the housing? Thank you for your help.

Hi,
I would say that the fan is stripped. It used to have a "D" shaped hole. To remove the nut, take out the plug and insert a looped length of small rope into the cylinder through the plug hole to block the piston's movement. Most are 9/16" and come off counter-clockwise.
Peace,
Clarke