My Petrol Chainsaw will not rev up

This article explains the checks you can carry out if your petrol chainsaw starts but does not reach full operating speed.

⚠️ Safety Notice

Ensure the chainsaw is operated in a safe, well-ventilated area when carrying out any running checks.

If you are unsure about adjusting the carburettor, please contact our Technical Support Team for assistance.

Possible Causes & Basic Checks

Check the Fuel

• Ensure the fuel is fresh and correctly mixed.
• Old fuel or an incorrect fuel-to-oil ratio can affect engine performance.

Check the Air Filter

• Inspect the air filter and ensure it is clean and free from debris.
• A blocked air filter can restrict airflow and reduce engine speed.

Check the Fuel Cap

• Ensure the fuel cap is fitted correctly and tightened by hand.

Check the Chain Brake

• Ensure the chain brake is fully disengaged before attempting to use the chainsaw.
• If the chain brake is engaged, the chain will not operate correctly.

Check the Carburettor Settings

If the checks above do not resolve the issue, the carburettor may require adjustment.

Carburettor Adjustment

⚠️ This procedure requires mechanical knowledge and the correct adjustment tool. Incorrect adjustments can affect engine performance and may cause further issues.

Tools Required

• Carburettor adjustment tool

Procedure

1. Start the chainsaw and allow it to warm up fully.
2. Locate the carburettor adjustment screws:
   • L = Low speed adjustment
   • H = High speed adjustment
3. Adjust the L screw until the engine idles smoothly without the chain rotating.
4. To adjust the H screw, run the chainsaw at full throttle.
5. Turn the H screw anti-clockwise until the engine struggles to reach maximum speed.
6. Slowly turn the H screw clockwise until the engine returns to normal operating speed.

If You Are Unable to Complete This Procedure

If you are not confident carrying out carburettor adjustments, please contact our Technical Support Team for assistance.

Depending on the fault, a replacement carburettor may be required. If your product is still within its warranty period, repair options may be available.

✔️ Summary

• Check fuel freshness and mixture ratio
• Clean and inspect the air filter
• Ensure the fuel cap is correctly fitted
• Confirm the chain brake is disengaged
• Check carburettor settings