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How to clean a spark plug

Excellent cleaning can be done with a wire brush, wd40 or spark plug cleaning tool. Learn the proper way to clean your spark plugs with BISON’s in-depth guide.

Table of Contents

Generator Spark plugs are like tiny lightning bolts! But don’t focus on their size; they are vital in starting a gasoline generator. They are responsible for generating the electrical spark that creates the ignition needed to start the engine. Another cool feature of spark plugs is that they clean themselves. You might be wondering how? Well, the heat generated by the engine can cause the spark plugs to burn everything.

So how can the spark plug be fouled? During the rainy season or when the generator is being serviced, the accumulation of moisture in the spark plug will cause the generator to fail to start. Also, if your vehicle is idling, dust and grime can build up on the spark plugs. In addition, over time, a carbon residue builds up on the surface of the spark plug. All of the above factors can lead to a decrease in spark plug efficiency. It will directly affect engine performance and fuel mileage. Now, no one wants that.

So, we will teach you how to clean your spark plugs and take some precautions to keep these little guys running smoothly.

cleaning generator spark plugs

Tools needed to clean spark plugs

Before BISON takes you through a step-by-step guide on how to clean your spark plugs, let’s review all the equipment and materials you’ll need:

  • Sandpaper
  • Compressed air can
  • Gloves
  • Carburetor cleaner
  • Spark plug cleaning tool
  • Spark plug gap tool
  • A clean cloth
  • Spark plug socket
  • Spark plug wrench
  • Pliers
  • Goggles
  • Blow torch
how to clean a spark plug

Three ways how to clean spark plugs

Method 1: Clean with abrasives

Clean the electrodes with sandpaper: A small pole will always stick out of the end of the spark plug. It’s called an electrode. If there is carbon buildup or discoloration, take sandpaper and rub it lightly until there is no carbon buildup.

Continue sanding the electrode until it looks like bare metal. Wearing goggles is recommended when sanding. Sandpaper is the best spark plug cleaner on the market.

Use a file to remove carbon deposits: Sandpaper should do the trick, but if it doesn’t, consider filling in stubborn deposits with a file. Place the file over the gap between the plug body and the electrode and slide it back and forth.

You can clean the threads with a wire brush: There may be oil and dirt on the plug threads. If there is oil on it, it is in the spark plug hole. Also, make sure to clean the spark plug hole before reinstalling the spark plug. Brushing the plug from a vertical angle easily removes deposits and debris from the threads. Then, turn and brush the plug from different angles.

Wear gloves when cleaning the plug with a wire brush so you don’t poke yourself. The thread doesn’t have to retain its color to work, but you must remove any deposits.

Carb cleaner to clean spark plugs

If you’re an entry-level mechanic, you’re probably wondering how to clean spark plugs with carb cleaner. Carb cleaner effectively cleans carbon deposits, buildup, grime, and debris from various generator parts.

To clean with a carb cleaner, place the spark plug on a clean surface, such as a vise, and spray the cleaner. After spraying the cleaner, make sure to wipe it with a clean towel. In addition to being clean, it dries quickly and leaves you with clean spark plugs.

If the carbon deposits are difficult to clean, you can use a wire brush and a carb cleaner. When you’re done, wipe the plug thoroughly with a clean towel or rag to dry any carb cleaner.

Repeat the process for all spark plugs at the same time. First, clean, reinstall, and plug the lead or ignition into that cylinder. If you’re wondering how to clean a spark plug with vinegar or how to clean a spark plug with gasoline, the process is similar to a carb cleaner.

You need to use a wire brush to brush off the carbon deposits on the plug and soak the plugin vinegar or gasoline for a few seconds.

cleaning alternator spark plugs using a blowtorch

Method 2: Using a blow torch

A blow torch can make the spark plugs very hot. Therefore, you need to use pliers to hold the plug to extend the length of the plug to prevent your hands from being burned.

Use pliers to grasp the plug at the connection end of the ignition coil. Hold the plug firmly without squeezing it, which may damage the plug. Pliers are only available as extensions. A bench vise is a better alternative to pliers.

Turn the knob on the propane or gas, place the ignition source in front of the nozzle, or gently press the ignition button. This ignites and keeps burning. Turn the torch on high until it begins to produce a blue flame.

Touching will burn off all the junk, debris, and oil on the spark plugs. Don’t be afraid to damage the plugs; they will survive the heat with no problem. Continue burning the spark plug while turning it until the electrodes and the end of the spark plug glow red.

Don’t let anything distract you or let the torch burn anything else. The burning process may take a few minutes, depending on your torch and its temperature.

Allow the spark plugs to cool down before holding them with your fingers. Plugs need to cool down before use. Care must be taken when handling spark plugs and blow torches; they will revert to standard color before they get cold. To avoid burning your hands, allow each plug to sit for 5 minutes before attempting to reinstall.

Method 3: Use a spark plug cleaning tool

Another proven method of cleaning spark plugs is to use a spark plug cleaning machine. The cleaning tool is designed to supply air and blast the spark plugs. This tool is very convenient.

To use this tool, secure the airbag, tighten the clip, and insert the air source. Press the button on the machine, plug in the spark plug, and switch the mechanism to sandblast. Shake the plug constantly so the cleaning tool blows off any carbon buildup. When you’re done blasting, switch the machine to air and blow off debris from the plugs.

We still recommend blowing the spark plugs with an air source. You don’t want debris falling into the cylinder.

cleaning alternator spark plugs with abrasives

How to Clean a Spark Plug – Step by Step

Step 1: Locate and remove the spark plug

As a general rule of thumb, ensure the engine is completely cool.

First, remove the engine cover. The spark plug is located in the combustion chamber cylinder below the ignition coil. To access them, use a wrench to unbolt the combustion chamber. Before doing so, brush away loose dirt and debris that could fall into the spark plug hole or combustion chamber. Remove the ignition coil from the cylinder. Insert the socket wrench consisting of the extension rod and spark plug socket to loosen the spark plug. Then carefully pull out the spark plug with pliers.

Step 2: Interpretation of spark plugs

Before you start cleaning your spark plugs, have them analyzed. Spark plugs tell the story of your engine. So check them out and find out what’s going on inside your alternator engine. Below is a brief overview of spark plug conditions and what they mean.

  • If the spark plug’s center electrode is worn, it needs to be replaced.
  • A dry, smoky appearance to the spark plug’s center electrode may indicate a fuel leak. You’ll need to check the spark plugs on all cylinders to verify; if there is a leak or an overall fuel control issue.
  • If you notice a slight discoloration in the spark plug’s center electrode, but no deposits, this is normal. This indicates that the spark plugs are functioning and the engine is working perfectly.
  • If the outer electrode of the spark plug has dry, sandy deposits, then there is a problem. The valve seals are not working, and oil is sucked into the cylinder. You need professional help to solve this problem.
  • If you notice a lot of wet, muddy deposits on the ends of your spark plugs, it’s a sign that you need to overhaul your engine for major internal repairs.
  • After checking your spark plugs, it’s time to clean them thoroughly.

Step 3: Cleaning spark plugs with Spark Plug Cleaner

Spark Plug Cleaner is great for cleaning spark plugs. Spray the Spark Plug Cleaner multi-purpose product on a microfiber cloth and wipe the spark plugs. You can even spray Spark Plug Cleaner directly on the spark plugs and wipe them with a clean cloth. After cleaning the spark plugs, put them back and start the engine to see the difference.

Preventive maintenance

Cleaner’s multi-purpose product not only helps in cleaning spark plugs but also in preventive maintenance. It acts as a lubricant, thereby reducing general wear. Spark Plug Cleaner removes moisture to improve connectivity and enhance its performance. Not only does it help remove rust, but it also prevents it. All in all, it’s the best chemistry for spark plugs.

Three methods of cleaning spark plugs

cleaning and replacing spark plugs

Modify the distance

Use a spark plug gap tool to measure the gap’s width.
Based on the engine manufacturer’s guidelines, you may need to expand or reduce the gap size. Specifications for the spark plug gap are made available by all engine manufacturers in owner’s manuals and on the internet. A spark plug gap of 0.020 to 0.030 inches is usually required for small engines.

re-install the spark plug

Re-attach the spark plug

Manually screw the spark plug back into the engine, then use a wrench to ensure it’s tightly secured. Affix the spark plug wire over the spark plug’s end. Wiggle the rubber boot slightly in both directions while placing it to confirm the connection is solid. Reposition any previously removed shield or cover. To verify your work, initiate the engine and let it run.

Cleaning vs. replacing spark plugs

Before replacing the spark plugs, we recommend cleaning them. It’s hard to tell if it needs to be replaced unless you’ve cleaned it and tried it again in your power tool or vehicle.

However, if you notice any damage, it’s time to purchase new spark plugs.

Damage includes:

  • Heavy carbon deposits that cannot be removed.
  • Cracks or breaks.
  • The electrodes on the top of the plug are burnt, blackened, green, or damaged.
  • If the spark plugs have been used for longer than the maximum recommended time, we strongly recommend that you replace the spark plugs. Clean the existing ones if it takes days or weeks to get new spark plugs. At the same time, it may help the vehicle run better.

For those who are looking for best spark plug for generator, you can find them here at BISON generator Parts Manufacturer. Always check what spark plugs your alternator needs before buying.


Learning to clean your spark plugs is an easy and cost-effective way to maintain peak engine performance and fuel efficiency. Following the step-by-step guidelines outlined in this blog post, you can easily remove carbon deposits and other contaminants that hinder spark plug function. Cleaning your spark plugs regularly will extend their life and keep your engine running smoothly, saving you time and money on potential repairs. Remember that safety is paramount throughout this process, so take the necessary precautions.

clean a spark plug FAQ

Technically, yes, you can clean the spark plugs, but it’s not usually worth it. We don’t recommend it for several reasons. Ultimately, a cleaned plug will not perform as well as a new plug.

If you have the extra budget, you can purchase an electric wire brush to clean your spark plugs faster and more effectively. Some people spray WD-40 or gasoline on the debris on the spark plugs to loosen them.

It is essential not to apply grease to the spark plugs but to know how and where to apply it. Since dielectric grease is an insulator, you’ll need to apply a small amount to the spark plugs individually. Don’t let it touch the metal connector on the boot. Pick up the oil with cotton wool and apply a small amount.

Apply a thin coat of electrical grease to the inside of the boot using a circular motion. For best protection, you can apply a layer of grease to the ceramic coating of your spark plugs. Use it again in the same circular motion. Make sure not to touch the grease on the metal terminals of the spark plug.

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