FAA Powerplant Written Practice Test

What happens to spark plugs when they are cleaned improperly?

1. They will always work perfectly

2. They can be damaged or rendered unusable

3. They perform better than new

4. They automatically self-correct

The correct answer is: They can be damaged or rendered unusable

When spark plugs are cleaned improperly, they can be damaged or rendered unusable due to a few factors. Spark plugs are precision components that are designed to create a specific spark for ignition in an engine. If they are cleaned with abrasive materials or methods that remove the protective coatings or change their physical structure, this can lead to several issues. Improper cleaning techniques can result in the erosion of the electrode surfaces, which impacts the ability of the spark plug to generate the required spark. Additionally, if contaminants such as oil or carbon deposits are not fully removed, they can interfere with the spark plug's performance, leading to misfiring or incomplete combustion. Moreover, excessive pressure or heat during cleaning can cause mechanical damage, such as cracks or bent electrodes. Once damaged, a spark plug may not perform as intended, leading to decreased engine efficiency, increased fuel consumption, and emissions problems. In some cases, a damaged spark plug may need to be replaced entirely, which can add to maintenance costs and downtime. Therefore, proper cleaning and maintenance techniques are crucial to ensure the longevity and proper functioning of spark plugs.