One key step to ensure that your lawn mower’s engine is happy is checking on your spark plug every once in a while. There are a ton of ways to tell if a lawn mower spark plug is bad but usually, you can tell your spark plug isn’t working as well as it could be if your engine doesn’t seem to be firing quite right. Sometimes all your spark plug needs is a quick cleaning in order to get it working properly again. Let’s get into how to clean your lawn mower’s spark plug.
When It’s a Good Idea to Clean a Lawn Mower Spark Plug
If you’re having issues with your mower’s spark plug, you’ll need to get it removed and assess the part itself. Once removed, you’ll be left with only two options, either clean or replace your spark plug. Here are a few cases in which it’s a good idea to clean your spark plug:
- Before trying to get a multimeter reading
- When testing for spark against grounded metal
- Roughly halfway through the spark plug’s lifespan (or mowing season)
- After having oil coming out of your lawn mower’s exhaust
If you run a test on your current spark plug after cleaning it and it still isn’t working properly, your best bet is to replace it. Since they’re an inexpensive part that should be replaced about once per season anyway, it doesn’t hurt to make a quick trip to the hardware store.
What You’ll Need to Clean Your Lawn Mower Spark Plug (Equipment List)
The tools required to clean a spark plug are pretty simple. Here’s a quick list of all the things you should have on hand before getting started:
- Insulated pliers
- Spark plug socket and wrench
- Soft wire or plastic brush
- Rubbing alcohol or brake cleaner
- Rags or paper towels
- A spark plug gap tool
How to Clean a Lawn Mower Spark Plug (Step By Step)
Once you have your tools all laid out, let’s get into how to clean lawn mower spark plugs. The upside to doing this job yourself is that you can apply this process to any small engine spark plugs. But before I go into the details of cleaning spark plugs, here’s a quick overview of the process:
- Remove your spark plug
- Look at the spark plug and see what has fouled it
- Clean the tip (side that was in the engine cylinder)
- Adjust the gap of the spark plug
- Screw the spark plug back into the engine and reconnect the ignition cable
Some people might be familiar enough with small engines to get going after this brief list, but if you’re anything like me, you’re probably hoping for some more details. I’ll go ahead and list some step-by-step instructions for how to clean a lawn mower spark plug below.
1. Get your Spark Plug Removed
Removal is probably the trickiest part when it comes to how to clean a fouled lawn mower spark plug. Luckily, figuring out how to remove a lawn mower spark plug is easy for anybody with the right tools.
The first step is to disconnect the spark plug cable from the terminal at the top of the spark plug. You’ll just need to gently pinch the spark plug hood with your fingers and wiggle it free. Then, set your spark plug socket securely on the spark plug’s base and loosen it completely. Once it spins freely, you can unscrew the spark plug the rest of the way with your fingers.
2. Examine the Business End of the Spark Plug
Assuming the first step went to plan, and you’ve got your spark plug out of the engine, you should take a look at its condition before doing anything else. Check the tip for sooty carbon buildup, wetness from oil and gas, scorching, or a chipped or broken electrode.
If the tip of the plug looks whole and clean and the threads on the sides are a normal tan or brownish color, look at the body of the spark plug. All you really need to do is make sure that the ceramic body isn’t cracked, and that the terminal where the ignition cable snaps on is in good shape.
3. Clean the Tip
If the body of the spark plug isn’t broken, and the end of your spark plug is dirty from carbon buildup, oil, gas, rust, or any combination of the four, you should clean it off. A workbench vice is really useful here but you can also clean your spark plug while holding it in your hand.
To start, drench the tip of your spark plug with either rubbing alcohol or brake cleaner. Once it’s wet, gently begin brushing off the entire end of your spark plug. It usually doesn’t take much to remove debris this way, but just reapply fluid and keep brushing to get any stuck-on gunk cleaned off.
After loosening everything up, give your spark plug a good wipe with your rag or paper towels and let it air dry completely. Rubbing alcohol and brake cleaner both evaporate almost instantly so this won’t take long.
4. Gap the Spark Plug
Now that you’ve gotten every bit of grime off the end of your spark plug, you need to check the gap. Learning how to gap a lawn mower spark plug isn’t too hard. You just need the correct tool to measure the small space between the end of the electrode and its grounding piece at the very tip of the spark plug.
Once you’ve made sure that the gap matches the manufacturer’s recommendation, you’re good to reinstall the spark plug back into the mower.
5. Reinstall the Spark Plug
The process of reinstalling a spark plug is exactly the same as removal, but backward. Start by threading the spark plug by hand to make sure that it’s set right. Next, tighten the spark plug with your socket wrench. Just don’t over tighten it or you’ll just create a big headache for yourself next time you need to take it out.
Once it’s secured in the engine cylinder, snap the spark plug hood back onto the spark plug’s terminal. Now that your ignition cable is reconnected, you’re ready to roll.
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