The Echo brand SRM-2100 trimmer/brush cutter is a professional-grade tool designed for outdoor use. The trimmer uses a nylon line spinning at high speeds to trim and edge grass in areas that traditional lawn mowers cannot access. The trimming line on an Echo SRM-2100 must be changed when it shows signs of wear or no longer cuts grass effectively.
Locate the drum assembly at the end of the shaft. Holding the drum in place, turn the circular spool on top of the drum clockwise until it will not turn any further. Pull upwards on the spool to remove it from the drum.
Locate the molded loop on the inside shaft of the spool between the two flanges. Thread a 40-foot piece of nylon line through the loop and adjust it so that one end of the line extends 6 inches further than the opposite end.
Press the two lengths of line against the spool body with your index finger and turn the spool so the line winds in the direction of the arrow labeled "CC". Continue winding until 8 inches of the shorter end of nylon line are left loose.
Tuck each line into a notch in the bottom flange in the spool. The notches are located on opposite sides.
Lay the drum right side up on a flat surface and position the spool above the drum so the hanging ends of line are aligned with the eyelet holes on the top edge of the drum housing. Feed each line through an eyelet hole and gently tug them loose from the notches in the spool.
Connecticut-based Stacy Morgan began writing for eHow in 2009. Morgan graduated from the Porter and Chester Institute of Technology with a certification in architectural drafting.