My Petrol Hedge Trimmer is not running correctly

Quick Answer

If your petrol hedge trimmer is difficult to start, runs unevenly, or will not start at all, checking the spark plug is a good place to begin. A dirty, damaged, or faulty spark plug can prevent the engine from igniting the fuel mixture correctly, resulting in poor performance or failure to start.

⚠️ Safety Notice

Before carrying out any maintenance:

• Switch off the hedge trimmer and allow the engine to cool completely.
• Remove the spark plug cap to prevent accidental starting.
• Work in a well-ventilated area away from open flames or sources of ignition.
• Wear suitable protective gloves and eye protection.

Tools Required

You will need:

• Spark plug spanner or wrench

• Wire brush (recommended)
• Clean cloth
• Petrol (for cleaning, if required)

Step 1: Remove the Spark Plug

1. Remove the spark plug cap (high-tension lead) from the spark plug.
2. Using a spark plug spanner, turn the spark plug anti-clockwise until it can be removed.

Note: The spark plug may be tight and require some force to loosen.

Step 2: Inspect the Spark Plug

Examine the spark plug for:

• Carbon build-up
• Dirt or oil deposits
• Worn or damaged electrodes
• Cracks in the ceramic insulator

A dirty or damaged spark plug may not produce a strong enough spark for the engine to start or run correctly.

Cleaning the Spark Plug

If the spark plug is dirty:

• Clean the electrode and threads using a wire brush.
• Alternatively, wipe the spark plug with a clean cloth lightly dampened with petrol.
• Allow the spark plug to dry completely before testing or reinstalling.

If the spark plug is excessively worn or damaged, replace it with a new one of the correct specification.

Step 3: Test for a Spark

1. Reconnect the spark plug to the spark plug cap.
2. Hold the threaded section of the spark plug firmly against a clean, unpainted metal part of the hedge trimmer to create an earth connection.
3. Ensure the Start/Stop switch is in the START position.
4. Move to a shaded area where the spark is easier to see.
5. Pull the starter cord while observing the tip of the spark plug.

Results

• A white or blue spark indicates the spark plug is working correctly.
• No visible spark may indicate a faulty spark plug or an ignition system fault.

Important: Hold the spark plug using insulated pliers or another insulated tool. Keep your hands away from the electrode during testing to avoid electric shock.

Step 4: Test with a Different Spark Plug

If you have access to a known working spark plug:

1. Connect it to your hedge trimmer's spark plug cap.
2. Repeat the spark test.

Results

• If the replacement spark plug produces a spark, your original spark plug should be replaced.
• If neither spark plug produces a spark, the fault may be with the ignition coil or another part of the ignition system.

Step 5: Reinstall the Spark Plug

1. Carefully screw the spark plug into the engine by hand to avoid cross-threading.
2. Tighten it securely using the spark plug spanner.
3. Push the spark plug cap firmly back into place.

If the Problem Persists

If your hedge trimmer still does not start or continues to run poorly after checking the spark plug:

• Check the fuel mixture is fresh and correctly mixed.
• Inspect the air filter and clean or replace it if necessary.
• Ensure the fuel filter is not blocked.
• If there is still no spark, the ignition coil or another ignition component may require inspection or replacement.

If you require further assistance, please contact our Technical Support Team.

Frequently Asked Questions

Why is my petrol hedge trimmer difficult to start?

Common causes include a dirty or faulty spark plug, stale fuel, a blocked air filter, or an ignition system fault.

What colour should the spark be?

A healthy spark is typically white or blue. A weak or absent spark indicates a fault.

Can I clean a spark plug instead of replacing it?

Yes. Light carbon deposits can often be removed with a wire brush. However, if the spark plug is worn, cracked, or damaged, it should be replaced.

What if there is no spark with a new spark plug?

If a known working spark plug also fails to produce a spark, the ignition coil or another ignition component may be faulty.

How often should I replace the spark plug?

Inspect the spark plug regularly and replace it if it shows signs of wear, damage, or poor performance, or according to the maintenance schedule in your user manual.