Trimmer: Trimmer Line Won't Feed

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 and locking into nubs as it waits to release the line. If the lever gets gummed up with debris or becomes worn down and will not unlock itself from the nubs, it is best to replace it. 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. 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, allowing the string to advance. If the spring is getting caught due to foreign material inside the housing, it can malfunction. To check the condition of the spring and clean out the housing, remove the bump head cap and inspect it. Clean out all debris from inside the housing and check that the spring and cap are in good working order. Replace parts as needed. Re-install the spring and bump cap.

The cap allows you to feed more line when you tap it on the ground. If this cap is broken or becomes badly worn over time (since it is in constant contact with the ground) it can malfunction, causing the line not to advance. Something could be blocking the cap, keeping the line from advancing. To inspect and replace, simply remove and clean out the bump cap housing of any debris that may be impacting its operation. If the cap is damaged, replace it.

The spool houses the wound trimmer line, located inside the trimmer head. If the line is too thick it can get stuck and fail to feed; if the line is too thin it may get overheated by friction when cutting, especially under heavier loads. If it gets too hot it can melt, fusing itself together on the spool. Make sure you are using the correct line thickness rated for your machine. Also make sure the line is wound the correct way on the spool.

The trimmer head houses the spool, cap, and spring (and in some models a lever). If the trimmer head itself is damaged badly enough from years of abuse, it can cause the parts to malfunction, requiring you to replace the trimmer head. Trimmer heads also become gummed up over time and require a good internal cleaning, which may reveal signs of severe wear. 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. Install the new trimmer head with the screwdriver or Allen wrench in place to prevent movement as you tighten the head down.