Jammed Line

• The nylon cutting line required for your Weed Eater needs to be properly sized. The line comes in different diameters. If you're using too large of a line or more than the recommended amount, the spool will stop working properly. These lines, if used improperly, can clog up inside the trimmer head. Improper use can also result in damage to the gearbox and driveshaft. Use only the line specified in your model's operator's manual.
  
  

Bent Spool

• The spool is made of a hard plastic. This plastic, while durable, can break from repeated hard tapping for line advancement. If the line stopped coming out and you started tapping the head over and over, the spool may have bent. If the spool is bent too far, it will break or crack. When this happens, the spool will no longer respond to the pressure and spit out more line when needed. Check the spool for damage every time you replace the cutting line.
  
  

Broken Spring

• The spool is housed on top of a metal spring. This spring responds to the tapping pressure and helps the spool feed the line out. Again, if the head was tapped too hard or too frequently, the spring ends may have sustained damage. If the spring ends are bent, the spring will stop connecting to the spool. Unhook the spring from the housing area, and check the ends to see whether they're bent or broken. Check the elasticity of the spring to make sure that it hasn't lost its efficacy.
  
  

Gearbox Problems

• The gearbox connects the cutting head to the driveshaft. If your spool and head are no longer interconnected, the spool will start showing signs of this problem. The gearbox can get clogged from long grasses or weeds, which can be sucked inside the head and wrapped around the gearbox. Dirt, rocks and other material can also cause damage inside the gearbox, which can show up as a problem inside the spool. Remove the entire cutting head and gearbox with a screwdriver, and inspect the gearbox for clogs or damage.