How to Change Spark Plugs on a Lawn Mower

Submitted by Anonymous (not verified) on Thu, 06/30/2022 - 8:00am

Spark plugs may be a small part of your lawn mower, but they are rather important. If a spark plug is old or not working properly, your mower’s engine can have difficulties starting or running. It is always good to check your spark plugs if you begin experiencing any of these issues.


How long does a lawn mower spark plug last?

For lawn mower spark plugs, the maximum lifetime from manufacturers is two years. While this is the maximum lifetime, it is not the ideal lifetime. For your engine to remain at optimum performance, it is recommended to replace your spark plugs once a year or after 30 engine hours. Since your lawn mower needs regular, annual maintenance, it is easiest to include replacing spark plugs as part of your maintenance routine.


What are the required tools for changing my mower’s spark plugs?

Changing your lawn mower’s spark plugs doesn’t take a lot of tools. The job can be done with a regular socket or a wrench and spark plug socket. Along with this, you will also need a spark plug gap gauge. The spark plug gap gauge is a tool to help you ensure the spark plug is installed to the exact measurements that the manufacturer recommends.


Instructions on proper installation of new lawn mower spark plugs

Replacing the spark plug in your lawn mower can be accomplished in six simple steps.

  1. Locate the spark plug(s). Zero-turn mowers usually have spark plugs on the side near the back of the engine. For push mowers and riding lawn mowers, look towards the front of the engine.
  2. Disconnect the spark plug lead. Once the spark plug is disconnected, remove any debris around the area.
  3. Use the spark plug socket or regular socket to remove the spark plug.
  4. Confirm the spark plug gap. While spark plugs usually come from the manufacturer already set to the correct gap, it is always smart to verify it is correct. Refer to your owner’s manual to see the proper size for your engine.
  5. Replace the spark plug. Make sure the threads are properly aligning by starting by hand. Once you’ve got the spark plug started, use your socket or spark plug socket to tighten until the bottom washer is compressed.
  6. Re-install the spark plug lead.


Where can I find lawn mower parts and service near me? 

Spark plugs can be an easy part of your lawn mower maintenance routine, but if you ever need help finding parts, your local Koenig Equipment is just a phone call or visit away. Do you prefer to have a certified technician work on your mower? Schedule a service appointment at Koenig Equipment, and one of our certified technicians can perform routine maintenance and replace your spark plugs.  



Order parts online using Koenig MyDealer:



Additional Resources:

Safety Tips for Riding and Walk-Behind Mowers

How can I Protect My John Deere Lawn Equipment with Performance Edge Maintenance Packages?

Winterize your Lawn Mower in 8 Easy Steps