If your Sun Joe cordless grass trimmer will not start, runs slowly, stops during use, vibrates, or does not feed or cut line correctly, use the checks below. Identify the model and cutting system first because string-spool and stringless-blade models require different procedures.

Models Covered

This guide covers the cordless grass trimmers currently listed in the Shop Joe Trimmers + Edgers collection. Bundle model numbers identify the complete kit; the included trimmer may have its own model label.

Compatibility reminder: A 20V ECOSHARP battery is not interchangeable with a 24V IONMAX battery. Use only the battery, charger, spool, line, blade, and other parts approved for the exact product model.

Before Troubleshooting

• Move to a dry, level, well-lit area away from people, pets, and electrical wires.
• Confirm that the safety guard and line-cutting blade, when equipped, are installed correctly.
• Do not use wire, rope, metal-reinforced line, or an unapproved cutting attachment.
• Do not continue testing a battery or charger that is cracked, swollen, leaking, unusually hot, wet, corroded, or otherwise damaged.

If the Motor Does Not Start or Runs Slowly

1. Inspect the Battery and Tool

   Remove the battery. Check the battery case, terminals, tool contacts, guard, cutting head, spool or blade, and housing for visible damage. Stop if anything is cracked, bent, loose, burned, melted, leaking, or wet.

2. Check the Battery Charge

   Press the battery charge-level button. If the charge is low, charge the battery with its approved charger. Allow a hot or cold battery to reach room temperature before charging or use.

3. Reinsert the Battery

   Slide the battery fully into the compartment until it is securely seated. Do not force it. On X20-TRIM-2A, inspect the connection prongs for damage before reinserting the battery.

4. Check the Cutting Head for a Jam

   With the battery removed, clear wrapped grass, weeds, and debris from the head, spool housing, guard, and ventilation openings. Make sure the cutting head can move as intended without obstruction.

5. Use the Correct Starting Sequence

   Install the battery, press and hold the safety or lock-off button, and then squeeze the trigger. Release the safety button only after the motor starts. Keep the trigger held to continue operation.

6. Reduce the Cutting Load

   If the tool runs slowly, do not force it into dense growth. Cut tall grass from the top down and use smaller passes. Keep the head free of wrapped vegetation and the motor vents clear.

7. Allow the Tool to Cool

   If the tool or battery became hot or stopped under a heavy load, release the trigger, remove the battery, and allow both to cool to room temperature. Do not repeatedly press the trigger after a protective cutoff.

8. Perform One Controlled Retest

   Reinstall the correct cutting attachment and charged battery, move to a clear area, and start the tool once. Stop and contact support if it still will not start, runs unusually slowly, or stops again.

If the String Will Not Advance

Use this section only for X20-TRIM-2A and 24V-ST14. Stringless models do not contain a spool.

If the Line Does Not Cut Off

1. Remove the Battery

   Release the trigger, remove the battery, and wait for the head to stop completely.

2. Inspect the Guard and Line Cutter

   Check whether the cutter is covered by debris, damaged, or missing. Do not operate without a correctly installed and undamaged guard and cutter.

3. Check the Line Length

   If the line extends beyond the guard, rewind or trim it so it reaches the line cutter. Do not operate with an excessive line length.

4. Escalate Damage

   Contact Shop Joe Customer Support if the guard or line cutter is loose, damaged, or missing. Do not improvise a replacement.

If a Stringless Blade Model Is Not Cutting Properly

Use this section for 24V-SB10-LTE and the stringless trimmers supplied with 24V-HT18-GT10-LTE or 24V-GT4MAX-LTE.

1. Remove the Battery

   Wait for the blade to stop completely before inspecting the cutting head.

2. Clear the Blade Area

   Remove grass, weeds, and debris from the blade, trimmer plate, slots, hub, guard, and ventilation openings.

3. Inspect the Blade

   Check for cracks, bending, tearing, severe wear, an enlarged mounting hole, or incorrect seating. Replace a damaged or worn blade with the exact approved part.

4. Confirm Correct Installation

   Install the blade in the orientation and mounting position shown in the exact model manual. Make sure it is fully secured before reinstalling the battery.

5. Adjust the Cutting Technique

   Use minimal pressure near concrete, brick, stone, or other hard surfaces. Do not force the blade. Allow it to do the cutting and keep it just clear of hard surfaces whenever possible.

If the Trimmer Vibrates Excessively

1. Stop Immediately

   Release the trigger, remove the battery, and wait for the cutting head to stop.

2. Remove Buildup

   Clear wrapped grass, weeds, and debris from the spool or blade, hub, guard, and head.

3. Inspect the Cutting Attachment

   Check for a cracked or worn spool, tangled line, a damaged blade, or an attachment that is not seated correctly. Replace damaged parts; do not straighten or repair them.

4. Reassemble Carefully

   Align and secure the approved spool or blade exactly as shown in the model's manual.

5. Stop if Vibration Returns

   After one controlled retest, remove the battery and contact support if excessive vibration continues.

Safety Stop Conditions

Escalation Path

Contact Shop Joe Customer Support when:

• The trimmer still does not start or continues to stop after the battery, starting sequence, temperature, blockage, and cutting load have been checked.
• The correct spool, line, blade, guard, battery, charger, or replacement part cannot be confirmed.
• The line-feed mechanism does not operate after the approved model-specific checks.
• Excessive vibration, unusual sound, overheating, smoke, sparks, or a burning odor continues.
• Any safety-related component is damaged, loose, or missing.

Have the model number, serial number, date code, battery and charger model numbers, purchase details, cutting attachment type, and a description of the issue ready. Contact Shop Joe Customer Support or call 1-866-225-9723.

Frequently Asked Questions