My Petrol Strimmer/Brush Cutter is revving too high

Quick Answer

If your petrol strimmer or brush cutter is revving unusually high while idling, the most common causes are the choke remaining engaged, the throttle hold (fast idle) not resetting, or a sticking throttle cable. Follow the checks below before seeking further assistance.

⚠️ Safety Notice

Before carrying out any inspection:

• Switch off the engine and allow it to cool completely.
• Keep hands clear of the cutting attachment.
• Wear suitable protective gloves.
• Do not attempt to adjust the carburettor unless you have the correct tools and experience.

If the cutting head rotates continuously at idle, stop using the machine until the fault has been resolved.

Why Is My Strimmer Revving Too High?

A high idle speed can be caused by:

• The choke remaining engaged
• The throttle hold (fast idle) not resetting
• A sticking or damaged throttle cable
• Incorrect carburettor adjustment
• An air leak within the engine or fuel system

Begin with the simple checks below.

Check the Choke Position

Ensure the choke has fully returned to the Run position.

If the choke remains partially engaged after starting, the engine may run incorrectly and idle at a higher speed than normal.

Reset the Throttle Hold

Many petrol strimmers have a throttle hold or fast-idle feature used during starting.

To reset it:

1. Hold the machine securely.
2. Press and release the throttle trigger.
3. Check whether the engine returns to a normal idle speed.

If the throttle hold has not disengaged, the engine may continue to run at higher revs.

Inspect the Throttle Cable

Check the throttle cable for:

• Kinks
• Twists
• Signs of wear or damage
• Anything preventing the cable from moving freely

The throttle should return smoothly when the trigger is released.

Important: Accessing or replacing the throttle cable may require partial disassembly of the machine. Unauthorised repairs may invalidate your warranty.

Frequently Asked Questions

Why is my petrol strimmer revving too high?

The most common causes are the choke remaining engaged, the throttle hold not resetting, or a sticking throttle cable.

Should the cutting head rotate at idle?

No. The cutting head should remain stationary when the engine is idling correctly.

How do I reset the throttle hold?

Simply press and release the throttle trigger after the engine has started. This normally disengages the fast-idle function.

Can a damaged throttle cable cause high revs?

Yes. A sticking, kinked, or damaged throttle cable can prevent the throttle from returning to its normal idle position.

Can I continue using the machine if it is revving too high?

No. Operating the machine with an excessively high idle speed can be unsafe and may cause damage. The fault should be corrected before further use.