6 Symptoms of Bad Spark Plugs

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Spark plugs are essential components in your engine’s cylinder head. Connected to the ignition coil, the spark plugs ignite the fuel and create combustion, essential to a running motor.

You may own multiple items that rely on spark plugs to run. Spark plugs can be found in cars, lawns mowers, snowblowers and more.

Bad Spark Plug Symptoms

Spark plugs must be clean and in good condition to ensure your motor runs efficiently. It’s common for spark plugs to become dirty, coated in oil, carbon or fuel, and for them to be damaged by too much heat. It is essential that you are aware of bad spark plug symptoms, as continued use of bad spark plugs can cause engine issues.

How to Tell if a Spark Plug is Bad

The following is a list of bad spark plug symptoms. If you start to notice any of the bad spark plug symptoms noted here, it may be time to replace your spark plugs:

  • Gas mileage may be reduced
  • Your check engine light is on
  • You may notice an inability to fully accelerate
  • Your engine may start to sound rough when idling
  • You may have trouble starting your vehicle
  • The engine might misfire more frequently

Spark Plug Replacement

If symptoms of bad spark plugs are ignored, and bad spark plugs continue to be used, this can eventually lead to more serious engine issues.

It is therefore important to take spark plug replacement seriously if you see signs of bad spark plugs.

Luckily, spark plug replacement is fairly straightforward, and will result in immediately noticeable improvement in terms of how your engine runs.

There are a few tools you will need to complete the spark plug replacement. Gather together the following spark plug replacement tools as the bare essentials for this project:

  • Spark plug socket
  • Flexible handle ratchet
  • Torque wrench
  • Spark plug gap gauge

Remember to take care of one spark plug at a time to avoid confusion.

How to Remove Spark Plugs

If you’re seeing symptoms of bad spark plugs, the following steps will help you remove each spark plug.

  1. Find the boot – this is where the spark plug wire connects to the spark plug itself. Hold the spark plug wire by the boot, twist and pull it to remove.
  2. Clean the area where the spark plug enters the block. This is so that once the spark plug is removed, surrounding dirt won’t fall into the space where it sat.
  3. Use the spark plug socket to loosen the plug. Turn the spark plug counterclockwise.
  4. The plug is likely to be tight, so if you’re having trouble loosening it, use a ratchet. 
  5. Ensure that the ratchet and the plug are at the same angle, to avoid stripping the threads.

Spark Plugs for Lawn and Garden

Spark plugs are found in a wide range of lawn and garden equipment. Spark plugs for lawn and garden include lawn mower spark plugs, snowblower spark plugs, chainsaw spark plugs, leaf blower spark plugs, and more.

When it comes to spark plugs for lawn and garden, some of the most popular brands include Craftsman, Toro, and Briggs & Stratton. Other brands include NGK, Hicello, OREGON, Qualtex, Wolf-Garton, RocwooD and more.

Seeing Signs of Bad Spark Plugs? Replace them at Repair Clinic

Repair Clinic has the spark plugs you need. For guidance and more information on spark plugs, or to purchase new spark plugs, visit Repair Clinic today.


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