Guide: How to Maintain My Spark Plug ?

MAINTENANCE

HOW DO I MAINTAIN MY SPARK PLUG?

The spark plug ignites the mixture and determines both starting and engine performance. If the machine struggles to start, stalls when cold or uses more fuel, the spark plug is often to blame. The good news: it is inexpensive and easy to replace.

ROLE OF THE SPARK PLUG & SIGNS OF WEAR

A spark plug in good condition ensures a steady spark, a clean start and clean combustion. Conversely, fouled electrodes, carbon build-up, a cracked insulator or a blackened base lead to misfires and poor performance.

WHEN TO CHANGE THE SPARK PLUG?

	Frequency: preventive replacement every 2 years (or sooner if wear is observed).
	After winter storage: if the machine started poorly in spring, begin with the spark plug.
	Symptoms: hard starting, loss of power, excessive fuel use, stalling, irregular spark.

SAFETY & REQUIRED EQUIPMENT

SAFETY

Cold engine, flat ground, brake on, spark plug cap disconnected.

TOOLS

Spark plug wrench, gap gauge (feeler), wire brush, cloth.

CONSUMABLES

A new spark plug if needed, a little dielectric grease.

STEP-BY-STEP MAINTENANCE

1	Disconnect the spark plug cap Blow around it to clear away dust.
2	Unscrew the spark plug With the right wrench, keeping the axis straight.
3	Inspect the base Light brown = OK. Oily black = too rich / oil. Chalky white = too lean / overheating.
4	Clean the electrodes With a wire brush (without damaging the insulator). Wipe the thread.
5	Set the gap & refit Screw back by hand, finish with the wrench without forcing, reconnect the spark plug cap.

CHECK THE ELECTRODE GAP

The electrode gap determines the quality of the spark. Measure it with a gap gauge (feeler). Refer to the manufacturer's recommendations (engine manual) and adjust gently by bending the ground electrode if necessary.

KEEP IN MIND

An incorrect gap can cause misfires and excessive fuel consumption.

CLEAN OR REPLACE?

CLEANING IS FINE

Light fouling, clean electrodes, intact insulator.

REPLACEMENT RECOMMENDED

Advanced wear, rounded electrodes, cracked insulator, damaged thread, stubborn deposits.

DISCOVER OUR SPARK PLUGS →

FIND THE COMPATIBLE REFERENCE

The reference is marked on the spark plug (above the base) if it is still legible. The most reliable source is the exploded view of your engine or your machine. Failing that, follow our guide "How to find the parts for your engine?".

QUICK DIAGNOSIS

SYMPTOM	WHAT TO CHECK
Hard starting	Try a new spark plug correctly gapped.
Loss of power / hesitation	Check the spark plug, then the carburation (air filter, mixture richness).
Excessive fuel use	Worn spark plug, incorrect gap or too rich a mixture.

MAINTENANCE CHECKLIST (RECAP)

	Cold engine, spark plug cap disconnected, clean area.
	Removal with the right wrench.
	Visual check of the base & the insulator.
	Cleaning with a brush + cloth.
	Gap measured and adjusted.
	Refitting: screw by hand then tighten moderately.
	Replacement if worn or faulty.

FREQUENTLY ASKED QUESTIONS

Can I sand the electrodes with sandpaper?

No, abrasive paper leaves residue and damages the surface. Use a small wire brush instead.

Should the spark plug be torqued?

Yes, ideally as per the engine manual. Otherwise, screw by hand until it seats, then tighten moderately with the wrench.

Grease on the spark plug cap: useful?

A very thin film of dielectric grease helps against moisture and makes removal easier. There is no need to apply any on the thread.

NEED HELP WITH YOUR SPARK PLUG?

To identify the reference or an equivalent, our advisors are here to help.

HOW DO I MAINTAIN MY SPARK PLUG?

NEED HELP WITH YOUR SPARK PLUG?

Do you have a question?