# Cordless strimmer not working: causes and fixes

Source: https://mowandedge.co.uk/blog/strimmer-not-working
Published: 2026-10-12
Publisher: Mow and Edge

**In short:** If a cordless strimmer will not start, check the battery is charged, warm enough and fully seated, and that any safety lock is released. If it runs but will not cut, the line has usually run out, snapped inside the head or welded to itself. If it cuts out, grass wrapped round the head or an overheated motor or battery is the usual cause.

Strimmers work hard in dusty, damp conditions, so faults are common, but most are simple to put right. This guide works through the problems in order: power, line feed, cutting out and unusual noises. It is written for battery strimmers, with a short section on corded and petrol models. Always remove the battery before touching the head.

## Quick diagnosis

Use the table to narrow down the cause before you start taking the head apart.

| Symptom | Likely cause | Try this |
| --- | --- | --- |
| Nothing happens | Battery, lock-off button, contacts | Charge and reseat battery, press lock-off, clean contacts |
| Motor runs, no line | Line run out, snapped or welded | Open the head and rewind or replace the spool |
| Line will not feed | Wound loosely or wrong way, wrong diameter | Rewind correctly with the right line |
| Cuts out | Grass wrapped round head, overheating, low battery | Clear the head, rest, swap battery |
| Vibration or noise | Uneven line, damaged head | Even the line lengths, check the head |

Strimmer symptoms and likely causes

Note: Remove the battery before cleaning or opening the strimmer head.

## No power at all

Make sure the battery is charged and pushed fully home. Many strimmers have a lock-off button that must be pressed before the trigger works. Batteries can refuse to work if they are very cold or hot, so bring a cold battery indoors to warm up. Clean dirty contacts on the battery and tool with a dry cloth.

If the battery does not charge, see our guide to [batteries that will not charge](https://mowandedge.co.uk/blog/cordless-mower-battery-not-charging); the same checks apply to strimmer batteries on a shared platform.

## Line will not come out

This is the most common complaint. Open the head and look at the spool. If it is empty, rewind or replace it. If line is still there, it may have snapped inside the head, crossed over itself or fused together from heat. Unwind and rewind it tightly in the direction of the arrow. Check that the diameter matches the manual.

[How to replace strimmer line](https://mowandedge.co.uk/blog/how-to-replace-strimmer-line)

## It keeps cutting out

Long grass wraps round the shaft just above the head, which makes the motor work hard and can trip overload protection. Remove the battery and pull the grass away. Cutting very long grass in one go also causes overloads; cut it down in stages. A battery nearing empty can cut out under load before the gauge shows it, so try a fresh one.

If the motor or battery feels very hot, stop and let them cool in the shade. Working in hot sun for a long session can trigger thermal protection.

## Rattling, vibration or poor cutting

Uneven line lengths unbalance the head and cause vibration. Trim both lines to the guard's cutter. A cracked head or worn eyelets also cause wobble and should be replaced. If the line seems to wear away fast, see [why strimmer line keeps breaking](https://mowandedge.co.uk/blog/strimmer-line-keeps-breaking).

## Corded and petrol strimmers

For corded strimmers, check the plug fuse, the extension lead and the RCD, and inspect the cable for damage. Never use a strimmer with a damaged cable. For petrol strimmers, stale fuel, a dirty spark plug and a blocked air filter are the usual causes of poor starting. A carburettor that needs cleaning is often a job for a service agent.

Note: Do not open the motor housing of a cordless tool. Faults inside should be handled by the maker's service agent, especially under warranty.

## When to repair or replace

A new spool, head or battery is a cheap fix. If the motor is faulty, compare the repair against a new tool. If you already own batteries, a bare tool from the same platform is often good value. Our [cordless strimmer guide](https://mowandedge.co.uk/best/best-cordless-strimmer) lists current models.

## Simple care that prevents most faults

After each session, remove the battery, brush grass from the head and the air vents on the motor housing, and check the line. Blocked vents make the motor run hot and cut out sooner. Store the strimmer and battery indoors, out of frost and direct sun. Before the first cut of spring, check the line is still supple and the head turns freely.

Treat the battery well and it lasts longer: avoid leaving it on a hot patio, do not store it completely flat for months and charge it at room temperature.

## Frequently asked questions

**Why is my strimmer running but not cutting?** The line has usually run out or snapped inside the head. Open it and rewind or replace the spool.

**Why does my strimmer line keep getting stuck?** Line wound loosely, crossed over or the wrong diameter. Rewind it tightly in the right direction.

**Why does my battery strimmer stop after a few seconds?** Often a low or cold battery, or overload protection. Clear the head, charge the battery and try again.

**Can I use any line in my strimmer?** Use the diameter and type the manual specifies.

## Buying guides on this topic

- https://mowandedge.co.uk/best/best-cordless-strimmer
- https://mowandedge.co.uk/best/best-cordless-mower-and-strimmer-set