DIY guide to replacing a leaf blower spark plug: When & how to do it

If your leaf blower’s been getting harder to start, losing power, or just doesn’t seem to be working as well as it used to, it could be time for a new spark plug.

Luckily, changing a spark plug is a simple job that can give your leaf blower a big boost so that it runs smoother and longer. And don’t worry — you don’t need to be a pro mechanic! With a few basic tools and a little guidance, you should be able to get your blower back in top shape in no time.

If you need any replacement parts for your leaf blower, you can enter your model number at AppliancePartsPros.com to order them. Most orders arrive in just two business days, and we have thousands of free guides to show you how to install your new parts.

Signs of a faulty spark plug

Being able to spot the signs that your spark plug is worn out can save you a lot of time and headache from a poorly running leaf blower. Here are a few clues that it’s time to get a new spark plug.

• Blower requires multiple pulls or cranking efforts to start
• Unit runs rough, sputters or misfires, which typically means that it’s struggling to get a consistent spark
• Higher fuel use than usual
• Weaker blower force or loss of power

NOTE: It’s a good rule of thumb to change the spark plug every season or after about 100 hours of use. Always check your blower’s manual for specific recommendations since different models may have unique needs.

Read more: Troubleshooting and Fixing a Leaf Blower that Won’t Start

What you’ll need

• Spark plug socket to remove and install spark plugs without damaging them
• Socket wrench to turn the spark plug socket
• Gap gauge to measure the gap on the new spark plug and help you adjust it to the correct size
• Replacement spark plug (Make sure you have the exact type and size for your blower model)

Safety precautions   

When working on any appliance, remember to keep safety first. Here are some tips to keep in mind: 

• If you’re working indoors, make sure there’s adequate ventilation to prevent the buildup of exhaust fumes.
• Wear insulated work gloves to protect your hands from sharp metal parts, pinching hazards and debris.
• Never attempt to service or repair the unit while it’s running or when the engine is still warm. Wait for all moving parts to come to a complete stop and unplug it.
• Be very careful when working near blades, augers, or any other moving parts. Keep your hands, fingers, and clothing clear of these areas at all times.
• If the appliance has recently been used, give it plenty of time for any hot parts to cool down before working on it. 
• Empty the gas tank before beginning any work. 
• When working with wires, avoid touching any exposed wires or terminals. If you need to touch a wire, use a non-conductive tool or wear insulating gloves to prevent electrical shock.
• Take your time and don’t rush while working to prevent accidents and personal injuries.
• Work in a well-lit area so you can clearly see and access the interior parts.
• Clear your workspace of clutter and other obstacles. Keep children and pets away from the work area.
• Be gentle when handling or removing parts. Excessive force might damage the appliance or cause injury.
• Wear safety glasses when working with chemicals, dust or cleaning large debris to prevent injury. 

Read more: The Ultimate Guide to Leaf-Blowing

How to check & replace the spark plug

NOTE: While we strive to offer helpful advice for DIY appliance repairs, the information in this article may differ from your specific appliance model. Variations in models and configurations can lead to differences in troubleshooting steps, error codes and part replacements. For the most accurate guidance, we strongly recommend consulting the technical sheet for your specific appliance model before beginning any testing or repairs.

Step 1: Take out the old spark plug

1. Make sure the unit is turned off.
2. Find the spark plug, which is usually in the front of the engine. If there’s a cover or cap over it, gently remove it. 
3. Attach the spark plug socket to the socket wrench, place it over the spark plug, and turn counterclockwise to loosen it. Once it’s loose, you can usually unscrew it the rest of the way by hand.
4. Take a look at the removed plug. If it’s covered in soot or is obviously worn out, you’ll need to replace it. If there’s any severe or unusual damage, it’s a good idea to inspect other parts of your blower.

Step 2: Set the gap on the spark plug

Before you try to install the new spark plug, it’s important to make sure it has the right gap size. The gap is the small space between the metal tip and the electrode at the end of the plug. Most manuals include the recommended gap size for your model.

Slide the gap gauge into the space on the spark plug. If it’s too small or too large, carefully adjust it by gently bending the metal tip until it matches the correct size.

Step 3: Install the new spark plug

1. Screw in the spark plug by hand as far as it will go. This helps avoid cross-threading, which can damage the threads on the plug or the engine.
2. Use the socket wrench to snug it up, but don’t overtighten it. Too much force can crack the plug or make it hard to remove later.
3. Reconnect any covers or cables that you removed earlier and make sure they’re securely reattached.
4. Start up your leaf blower to see how it’s running. Listen for smooth, steady sound without misfires or sputtering.

Read more: How to fix a leaf blower that starts and then stalls

More for you

Thanks for following along! We hope this guide helped you replace the spark plug in your leaf blower. If you still need some parts, just grab your model number and head over to AppliancePartsPros.com to search for them. With over two million parts in stock, most orders ship the same day and arrive within just two days. 

Need more assistance? Our team is here at 1 (877) 477-7278 or through online chat or email. While your part is on its way, why don’t you check out our DIY blog and YouTube tutorials? And remember to stay in touch by following us on Facebook, X and Instagram!