Grass trimmer or brushcutter loses power while cutting. What to check?
If your Husqvarna grass trimmer or brushcutter loses power while you are cutting, the cause is usually related to fuel, airflow, the cutting attachment or engine performance.
Many of these issues can be resolved with a few simple tricks.
Quick check
Before troubleshooting, check these three things:
- Is the fuel fresh and correctly mixed?
- Is the cutting attachment and guard installed correctly?
- Is the air filter clean?
If everything looks correct, continue with the checks below.
Most common causes and fixes
Old or incorrect fuel
Fuel that has been stored for too long or mixed incorrectly can reduce engine performance.
What to do:
- Replace old fuel with fresh fuel
- Use the correct fuel mixture recommended for your model.
Old fuel is one of the most common causes of power loss in petrol-powered grass trimmers.
How to mix fuel for grass trimmers and brushcutters
Air filter is dirty
A clogged air filter restricts airflow, making the engine work harder and reducing power.
What to do:
- Remove the air filter
- Clean or replace if necessary
A clean air filter helps maintain the correct air-fuel mixture and engine performance.
Blocked fuel system
If fuel cannot reach the engine efficiently, power drops when the machine is under load.
Possible causes include:
- Dirty fuel filter
- Blocked fuel line
- Carburettor deposits
These issues usually become noticeable when you begin cutting rather than when the engine is idling.
Engine overheating
If power gradually decreases during longer jobs, the engine may be overheating.
What to do:
- Stop using the machine
- Allow it to cool
- Check that cooling vents are clean
When should you stop using the machine?
Stop using your grass trimmer or brushcutter if:
- Engine power continues to decrease
- The engine stalls repeatedly
- You notice unusual vibration or smoke
- The machine makes abnormal noises
Continuing to operate the machine may cause further damage.
How to prevent power loss
Regular maintenance helps keep your trimmer performing at its best:
- Use fresh fuel
- Clean the air filter regularly
- Replace worn trimmer line or damaged blades
- Keep the cooling system clean
- Inspect the cutting attachment before each use
Still losing power?
If you’ve completed the checks above and the problem continues: