Cleaning and replacing your spark plugs is a key part of regular lawn equipment maintenance. The good news is they're also one of the easiest parts to remove and replace. They're pretty inexpensive, and if you learn to do spark plug maintenance yourself you'll also save money that way. Keep reading to learn how to remove a spark plug, figure out whether it should be cleaned or replaced, and then put a spark plug back in properly.


Removing the Spark Plug

First, disconnect the spark plug lead. That's the wire that fits over the top of the plug. Next, clean the area around the spark plug. You don't want any debris on the outside around the plug falling into the combustion chamber. Once everything is clean, use a ratchet and spark plug socket to remove the plug from the mower.

Clean the Plug

It's hard to tell whether or not the plug should be replaced until you start cleaning it. A wire brush is the best tool to use for this. In a pinch, you can use fine-grain sandpaper. Simply brush over the top of the plug to remove carbon deposits. You can also use spray-on plug cleaner along with the wire brush or sandpaper to help get the plug extra-clean if you're hoping to make it last longer.

Inspect For Damage

This is the step where you decide whether it's worth it to keep cleaning the spark plug or whether you need to buy a new one. Take a good look at your spark plug and check these three things:

  • If there are heavy carbon deposits, try scraping them off with a strong knife. When deposits come off, you're good to move on to the next step. If not, you'll need a new spark plug.
  • Are there cracks in the plug? Cracked porcelain or any breaks in the plug mean it should be replaced.
  • Look at the electrode at the top of the spark plug. If it looks burned and black, if it's turning green, or if there is damage to the metal (such as if it looks melted or pitted) then it's time for a new plug.

If you decide you need a new spark plug you can pick one up at Richardson Saw and Lawnmower. We carry a wide variety of different plugs and we can help you make sure you get the right one for your small engine.

Check The Gap

If your spark plug looks good to go, it's time to check the gap. You can technically skip this step, but making sure the gap is right will increase the life of your spark plug and make the engine start better. For this task you'll need a spark plug gauge. A gauge measures the distance between the electrodes at the tip of the spark plug. The correct gap is usually .030 inche, but you should check the specifications for your equipment just to be sure. If the gauge is off, adjust it before putting the plug back in your engine.

Replace the Plug

To put the old plug back or install a new plug just reverse the steps you used to take it out. Put the plug back in its place and use a ratchet and spark plug socket to tighten it. Be careful not to over-tighten. Replace the spark plug lead wire and start your engine. Everything should be running good as new!