Turn off the Echo 210 weedeater engine before attempting to replace the trimmer line.
Place the engine side of the weedeater on the ground with the head up in the air. Lean the head forward at an angle and hold the weedeater shaft securely between your legs with the engine behind you.
Grasp the head cover and turn it counterclockwise to twist it off. Remove the trimmer line spool and dispose of any remaining line.
Insert the end of the new line through the line anchor on the spool and wrap the line tightly around the spool until only 4 to 5 inches is remaining.
Set the spool in place on the weedeater head and insert the end of the line through the trimmer line feed port in the head. Replace the head cover and twist it clockwise to tighten it.