Imagine this: it's a Saturday morning, and you're out in the yard, ready to mow the lawn. You fill up your gas tank, grab the spark plug wire - and then realize that you have yet to learn how often to replace spark plugs. Don't worry. We've all been there.
The good news is that spark plugs typically only need to be replaced every 100 hours of mowing - and with proper care, they can last even longer. So, if you're keeping up with your lawn care schedule, you should be fine. However, if you notice that your spark plugs are starting to wear out sooner than usual, it might be time to invest in a new mower.
Evaluate and remove the spark plugs. Plugs that are corroded or cracked must be replaced. Remember, spark plugs are generally only designed for 100 hours of mowing. So you can trust that they're much cheaper to replace than the entire mower.
You can identify a bad spark plug by looking at it. Use a socket wrench to unscrew the plug to inspect the electrode and insulator. Look closely: the center of the electrode should have a flat top. If it appears rounded, cracked, or blackened from carbon or degraded excess fuel, it's time to replace it.