My Petrol Strimmer head/Brush Cutter blade will not move

This article covers the basic checks you can perform if the strimmer head or brush cutter blade is not rotating when the engine is running.

Contents

• Check the Head or Blade Installation
• Check the Shaft Connection
• Inspect the Drive Shaft

Check the Head or Blade Installation

Before carrying out any further checks, ensure that the strimmer head or brush cutter blade has been installed correctly.

If you have recently changed between a strimmer head and a brush cutter blade, refer to the relevant installation guide and confirm that all components have been fitted and secured correctly.

Check the Shaft Connection

If the cutting attachment is installed correctly but still does not rotate, check that the upper and lower shaft sections are properly connected.

A loose or incorrectly assembled shaft connection can prevent drive from being transferred from the engine to the cutting head.

Inspect the Drive Shaft

The most effective way to diagnose the issue is to check whether the internal drive shaft is damaged, bent, twisted, or disconnected.

Step 1 – Separate the Shaft Sections

Carefully disconnect the upper and lower shaft sections according to the instructions in your user manual.

Step 2 – Check the Lower Shaft

1. Rotate the strimmer head or brush cutter blade by hand.
2. While doing so, look down the lower shaft tube.
3. The internal drive shaft should rotate smoothly and consistently.

Result:

• If the drive shaft does not rotate smoothly, the lower shaft assembly is likely damaged and may need replacing.
• If it rotates correctly, proceed to the next step.

Step 3 – Check the Upper Shaft

⚠️ Warning: Take extra care when carrying out this check. Keep hands, clothing, and loose objects clear of any moving parts.

1. Start the engine.
2. Look down the upper shaft tube.
3. Gently apply throttle while observing the drive shaft.

Result:

• If the drive shaft rotates smoothly, the issue may lie elsewhere in the drive system.
• If the drive shaft does not rotate, the upper shaft assembly or drive mechanism may have failed and require replacement.