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Fix a string trimmer that will not feed line

We'll rule out empty spool, jammed line, and bump head issues—then isolate the cause or tell you when to call a mechanic.

Troubleshooting · Home appliances
10–25 min
What you'll need
  • Trimmer line (correct diameter per manual)
  • Screwdriver or trimmer tool (if needed to open head)
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Steps

Goal: Confirm the engine runs, then rule out empty spool, jammed line, and bump head issues.

  • Start the trimmer and confirm the engine runs. Tap the bump head on the ground while the head spins. Line should advance.
  • Good: Engine runs but no line—spool or bump issue. Proceed to Reload the spool.
  • Bad: Engine does not run—see fix-string-trimmer-will-not-start.

Reload the spool

Goal: Confirm the spool has line and is wound correctly.

  • Remove the spool from the head. Check how much line remains. If empty or nearly empty, reload with the correct diameter per your manual.
  • Wind the line in the direction of the arrows on the spool. Thread the ends through the eyelets. Do not overfill.
  • Good: Spool has line wound correctly. Proceed to Clear a jam if line still does not advance.
  • Bad: Empty spool—reload and retest.

Clear a jam

Goal: Remove tangled or stuck line from the head.

  • Stop the engine. Remove the spool. Pull out any tangled or stuck line.
  • Clean the exit holes and head interior of debris or melted line.
  • Reinstall the spool and retest. Bump the head to advance line.
  • Good: Line advances after clearing.
  • Bad: Still no advance—proceed to Check bump mechanism.

Check bump mechanism

Goal: Confirm the bump head mechanism engages the spool.

  • Inspect the spring and pawl inside the head. They must engage the spool when you tap the head.
  • If the pawl is worn or the spring is broken, the head may not advance line. Replace the head if damaged.
  • Good: Mechanism engages and line advances.
  • Bad: Worn or broken—replace the head or call a mechanic.

When to get help

Call a mechanic if:

  • Reloading, clearing jams, and checking the bump mechanism do not fix it.
  • The head assembly is broken or worn.
  • You need a head replacement and are not comfortable doing it.

Verification

  • Line advances when you bump the head on the ground.
  • Line extends past the guard and trims properly.
  • No tangling or jamming during use.

Escalation ladder

Work from the device outward. Stop when the problem is fixed.

  1. Confirm symptom Verify the engine runs but line does not advance when you bump.
  2. Spool and line Check spool has line; reload if empty; use correct diameter.
  3. Clear jam Remove tangled or stuck line; clean exit holes.
  4. Bump mechanism Inspect spring and pawl; confirm head type.
  5. Call a pro Head broken or worn; will not advance after all steps.

What to capture if you need help

Before calling support or posting for help, have these ready. It speeds everything up.

  • Head type (bump feed vs fixed)
  • Line diameter and winding direction
  • Whether line is jammed or tangled
  • Steps already tried

Does the engine run but line does not advance when you bump?

Start the trimmer. Tap the bump head on the ground while spinning. Line should extend.

Confirm the engine runs. Bump the head. Good: Engine runs but no line—spool or bump issue. Bad: Engine does not run—see fix-string-trimmer-will-not-start.

Yes No

You can change your answer later.

Engine does not run

See fix-string-trimmer-will-not-start for no-start troubleshooting.

Done

Is the spool empty or nearly empty?

Remove spool and check line remaining.

Remove the spool. Check line. Good: Spool has line—check for jam. Bad: Empty or nearly empty—reload with correct diameter.

Yes No

You can change your answer later.

Reload the spool

Wind line onto spool in direction of arrows. Thread through eyelets. Use correct diameter. Retest.

Done

Is the line jammed or tangled?

Line stuck inside head or at exit holes.

Remove spool. Pull out tangled line. Clean exit holes. Reinstall and retest. Good: Line advances. Bad: Still no advance—check bump mechanism.

Yes No

You can change your answer later.

Clear jam and retest

Remove spool, clear tangled line, clean exit holes. Reinstall. Bump to test.

Done

Does the bump mechanism engage?

Spring and pawl must engage spool when you bump.

Inspect spring and pawl. Bump head and watch for engagement. Good: Mechanism works—check line diameter and winding. Bad: Worn or broken—replace head or call a pro.

Yes No

You can change your answer later.

Replace head or call a pro

Worn bump mechanism. Replace the head assembly or call a mechanic.

Done

Call a mechanic

Spool loaded, no jam, bump works—still no feed. Check line diameter and winding. If all correct, call a pro.

Done

Reviewed by Blackbox Atlas

Frequently asked questions

Why would a string trimmer not feed line?
Common causes: empty or nearly empty spool, jammed or tangled line, worn bump mechanism, incorrect line winding, or wrong line diameter. Reload the spool and clear jams first.
Can I fix a string trimmer that will not feed line myself?
Yes. Most feed issues are spool-related. You can reload the line, clear jams, and check the bump head with basic tools. A worn or broken head may need replacement.
When should I call a mechanic for a string trimmer that will not feed line?
Call a mechanic if the bump head is broken or worn and will not advance line after reloading; or if the head assembly needs replacement.

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