Trimmer: Trimmer Line Feeds Too Much or Continuously

The guard is located around the trimmer head, and protects you from debris flying upwards and hitting you during use. The guard itself will not cause the line to continuously advance or get too long, but there is a blade located on this guard that breaks the line off, keeping it from getting too long. Usually this vibrates off or gets dull over time. If left without a blade, the trimmer line will damage the guard, and you will have to replace the guard. The blade is bolted onto the guard. To replace the blade simply remove the old one and install the new one.

Some trimmers are equipped with an auto-line spool, which is controlled by a lever. This lever is located inside the trimmer head and works on centrifugal force, feeding out more line as the line wears away. The lever locks into nubs as it waits to release more line. Over time, this lever can wear down and it will allow the line to continuously feed out. To replace this lever, remove the trimmer head cap then remove the spool. Insert a small screwdriver under the base of the lever and pop it off. Insert a new lever by just pressing it on. Finally, re-install the spool and cap.

The spring keeps pressure on the bump head cap and returns the cap to its original position after you bump it, to allow more string to advance. Over time, it can become weak and impact the performance of the wire feed. To replace this spring, remove the bump head cap and remove the old spring. Install the new spring by pressing it on the bump head then reinstall the bump head back into the spool.

The cap allows you to feed more line when you tap it on the ground. If this cap is broken or worn out over time, it can malfunction, causing too much line to feed out when you bump it. Depending on its damage, it could be getting hung up as it tries to return, allowing the line to continuously advance. To replace it, simply remove and replace the bump cap with a new one.

The spool houses the line for the trimmer and has the line wound around it. It is located inside the trimmer head. If the line is too thick or too thin it can continuously feed the line. Make sure you are using the correct line thickness rated for your machine.

The trimmer head is the unit that houses the spool, cap and spring, and lever (in some models). If the trimmer head itself is damaged, it can cause the parts inside of it to malfunction to the point where replacing the inside parts will not work, requiring you to replace the entire trimmer head. To remove the trimmer head, insert a small screwdriver or Allen wrench into the hole on the gear box, located just above the trimmer head. Rotate the trimmer head until the screwdriver locks into place. On some models, you might have to lock the screwdriver in place against the washer, after it is locked inside the hole. Remove the trimmer head by rotating it counter clockwise. Trimmer heads are reversed-thread. Install the new trimmer head with the screwdriver or Allen wrench in place to prevent movement as you tighten the head down.