Small Engine Parts Focus: Spark Plug & Engine Maintenance

A spark plug performs two primary functions in a small engine. The first is to ignite the air/fuel mixture by an electric spark and the second is to remove heat out of the combustion chamber.

How often should a spark plug be changed?Small Engine Spark Plug

The electrodes on a small engine or lawn mower spark plug must be clean to produce the appropriate spark for ignition. The spark plug is constantly exposed to extreme temperature variations, chemicals, fuels and oils. That’s why the engine experts here at Briggs & Stratton recommend changing the spark plug every 100 hours of engine operation. If you don’t run your mower 100 hours over the course of the season, it is recommended to change it at the beginning of every season as part of your regular engine tune up maintenance. Doing so will ensure that there is a consistent spark, improve fuel economy and provides more reliable starting. Check out these instructions on how to change the spark plug or how to clean or inspect the spark plug.

What happens when you don’t change a lawn mower spark plug?

If you do not change the spark plug as recommended, carbon deposits may form on the head of the spark plug and cause difficulty when trying to start the mower. The more dirty or worn a spark plug is, the more voltage required to produce an adequate spark. If the mower is running and there is inconsistent firing, this is known as a spark “miss” and results in sluggish operation and poor acceleration.

Because Briggs and Stratton has a variety of engines and equipment configurations, always refer to your operator’s manual when servicing your product such as finding the right spark plug for your lawn mower. Your local authorized Briggs & Stratton dealer can also answer any questions you may have about small engine repair and maintenance.

NOTICE: Customer service questions are not monitored via the blog. If you need assistance with your Briggs & Stratton engine or power equipment, please contact our Answer Center or post your question to our User Community.