# Hedge trimmer not working: causes and fixes

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

**In short:** Most hedge trimmers that will not run have a simple cause: the two-hand safety switch is not fully engaged, the battery is flat, cold, hot or not seated, or the blade is jammed with sap or a stem. If it runs but will not cut, the blade is usually blunt, gummed up or the stems are thicker than the tooth gap.

A hedge trimmer that stops halfway along the hedge is frustrating, but most faults are easy to find. This guide works through the causes in a sensible order, from switches and batteries to blades and overload protection, and explains when to stop and take the trimmer to a repairer. It focuses on cordless trimmers, with notes for corded and petrol models. Always remove the battery or unplug the trimmer before you touch the blade.

## Quick checks

Start with these simple checks before you take anything apart or book a repair.

| Symptom | Likely cause | First thing to try |
| --- | --- | --- |
| Will not start | Safety switch, battery, lock button | Grip both handles fully, reseat a charged battery |
| Starts then stops | Overload or battery protection | Let it cool, cut thinner stems, charge the battery |
| Runs but will not cut | Blunt or gummed blade | Clean, oil and sharpen the blade |
| Blade jammed | Stem or debris trapped | Remove battery, clear the blade with gloves |
| Unusual noise or vibration | Loose or damaged blade, gearbox | Stop and inspect; get it serviced |

Hedge trimmer symptoms and likely causes

Note: Always remove the battery or unplug the trimmer before touching the blade.

## It will not start

Nearly every hedge trimmer has a two-hand safety system: a switch on the rear handle and a lever or grip on the front handle. Both need to be pressed, often in a set order, and some models have a lock-off button too. Read the manual and try again with a firm grip on both.

For battery models, check the battery is charged and clicks fully into place. Look at the charge indicator if there is one. Batteries also shut down if they are too cold or too hot, so let a battery warm up indoors or cool down in the shade. Clean the contacts with a dry cloth if they look dirty. For corded models, check the plug, fuse, extension lead and RCD.

[Battery not charging? Troubleshooting](https://mowandedge.co.uk/blog/cordless-mower-battery-not-charging)

## It starts then cuts out

Many cordless tools have overload protection that cuts the power if the motor is strained. Forcing the trimmer into thick wood, cutting in very dense growth or a blade clogged with resin can all trigger it. Release the switches, let the trimmer rest for a moment and try again on thinner growth.

A battery near the end of its charge can also cut out under load before the indicator shows empty. Swap to a freshly charged battery. If the trimmer cuts out frequently even on light work with a full battery, the battery may be ageing or there may be a switch or motor fault.

## It runs but will not cut cleanly

If stems are torn or the blade bounces off them, the blade is either gummed up, blunt or the stems are thicker than the tooth gap. Clean the blade with a resin remover, oil it and try again. If that does not help, see our guide on [sharpening hedge trimmer blades](https://mowandedge.co.uk/blog/how-to-sharpen-hedge-trimmer-blades). For thick stems, use loppers or a pruning saw.

## The blade is jammed

Remove the battery or unplug the trimmer first. Wearing thick gloves, pull out any trapped stems or debris. Do not try to free a jam by switching the trimmer on and off. If the blades will not move freely once clear, a blade may be bent or the gearbox damaged, and the trimmer should be checked by a service agent.

Note: Never put your fingers between the blades with a battery fitted or the plug in.

## Petrol hedge trimmers

If a petrol trimmer will not start, check the fuel is fresh and mixed in the right ratio, the choke and primer are used as the manual describes, the spark plug is clean and the air filter is not blocked. Old fuel left over winter is a common cause. If it starts and then dies, the carburettor may need cleaning, which is a job for a service agent if you are not confident.

## When to get it repaired

Stop using the trimmer and get it checked if you notice burning smells, smoke, sparks, a cracked casing, a damaged cable, loud grinding from the gearbox or a blade that wobbles. Check the warranty before opening the casing, as that can void it. For battery tools, a faulty battery is often the cause; a replacement from the same platform may be all you need. Our guide to [battery platforms](https://mowandedge.co.uk/blog/mower-battery-platforms-explained) explains compatibility.

## Preventing problems

Most hedge trimmer faults come from a dirty blade, a tired battery or forcing the tool. Clean and oil the blade after each use, store batteries indoors over winter and cut thick stems with loppers. If you are replacing a worn out trimmer, buying one on the battery platform you already own saves money and space. Our [cordless strimmer guide](https://mowandedge.co.uk/best/best-cordless-strimmer) shows which platforms we cover.

## Frequently asked questions

**Why does my cordless hedge trimmer keep stopping?** Usually overload protection, a low battery or a blade clogged with resin. Let it rest, charge the battery and clean the blade.

**Why will my hedge trimmer not start?** Check that both safety handles are fully pressed, the lock button is released and the battery is charged and seated.

**Can a hedge trimmer battery be too cold?** Yes. Lithium batteries can refuse to work when very cold. Warm it to room temperature first.

**Is it worth repairing a hedge trimmer?** A new blade or battery is often worthwhile. Motor or gearbox repairs depend on the age and value of the trimmer.

## Buying guides on this topic

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