How to check a lawn mower spark plug gap

The spark plug gap on your Husqvarna lawn mower is an air gap between the ground electrode and the centre electrode.

If the gap on your lawn mower’s spark plug is too small, the spark struggles to ignite the fuel and air mixture. If the gap is too large, it can make it difficult for the spark to bridge the gap for the lawn mower spark plug.

Over time, the electrodes wear away due to the constant arcing of sparks.

This can lead to the gap becoming larger and might result in difficulties with starting your lawn mower.

Measuring the spark plug gap on a lawn mower

To measure the spark plug gap on your lawn mower you can use:

• A feeler gauge
• A coin
• A wire
• A blade

Use the tool to measure the gap by sliding it between the electrode tips.

Place the correct blade or wire from your gap tool between the tips of the electrode, or use a coin to find the measurement.

Be careful not to touch centre electrode, as damaging it will require you to replace the spark plug.

Checking if the lawn mower’s spark plug gap needs adjusting

If the tool goes through the gap without touching the electrodes, the gap is too wide.

If the tool does not fit through the electrodes, the gap is too small and needs to be widened.

If the tool fits closely to the specified measurements, the spark plug is ready to be installed.

Adjusting the electrode gap on a lawn mower

Hold the spark plug with the electrode facing down.

To narrow the electrode gap, gently bend the bottom electrode towards the other one.

• If you are struggling to adjust the gap with the tool, try pressing the electrode gently against a flat surface like a table.

To widen the electrode gap, gently bend it outwards.

• Never bend too much. Always use very light pressure, as spark plugs are delicate and can break easily, causing misfires.

After adjusting the electrode gap, make sure to re-measure it so that it is correct for your lawn mower.

Correct electrode gap for my Husqvarna lawn mower

Depending on the type of lawn mower you have, the electrode gap can vary.

Always check your lawn mower’s operator’s manual for the correct electrode gap.