How to Check and Clean a Spark Plug

That feeling you get when your mower fires right up on the first pull? Pretty great, right?

You can thank your spark plug for that. Spark plugs play a pivotal role in the ignition process. If they are worn or dirty, your engine won’t start or you’ll have to try many times to fire it up. Spark plugs are inexpensive and easy to clean, so if a damaged spark plug is your problem, you’re in luck.

Spark plugs should be checked regularly during your standard mower maintenance routine. They may need to be checked or replaced:

  • Once each season.
  • After 25 hours of use.
  • If your lawn mower or outdoor power equipment won’t start.

With the steps below, you should be prepared and able to check and change a spark plug yourself. Time to roll up your sleeves and get to work!

How to Check for a Fouled or Damaged Spark Plug

  1. Disconnect the spark plug lead. Clean the area around the spark plug.
  2. Remove the spark plug with a spark plug socket.
  3. Clean the plug with a wire brush and in a well-ventilated space spray-on plug cleaner. Never clean a spark plug with a shot blaster or abrasives.
  4. Inspect the spark plug for deposits, cracks or burns. If these exist, replace the spark plug.
  5. Check the spark plug gap and adjust, if necessary.
  6. Replace the plug, re-attach the spark plug lead and start your engine.

How to Change a Spark Plug

  1. Locate the correct spark plug(s) and adjust gap settings.
  2. Disconnect the spark plug lead and remove with a spark plug socket.
  3. Replace with your new plug and re-attach the spark plug lead.

If your spark plug is fouled or needs replacing, you can look up your engines’ specific information to the part you need here.

If you need further assistance, check out our full list of Frequently Asked Question on Repairing Small Engines or contact a Briggs & Stratton service dealer near you.



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.