Cleaning spark plug is a relevant and quite adequate way to eliminate problems with the ignition of a gasoline engine. These include skips, missing or weak spark. Cleaning spark plug will not help if they are pierced, melted, or there are other problems in the ignition system. Also, do not bother if the cheapest ones are installed in the motor - it is easier and more reliable to buy new ones.

What does the correct cleaning of spark plug give?

The function of a gasoline engine spark plug is to generate a sure spark when high voltage is applied to it. It ignites the air-fuel mixture in the combustion chamber. In order for the motor to start well, work stably at idle and develop rated power, a spark must jump at each cycle, moreover, strictly between the electrodes with a correctly set gap.

A spark plug contaminated with soot cannot cope with this function, since oil soot is an excellent dielectric. When it accumulates on the electrodes, the spark most often hits off-center or barely. As a result, it has a low temperature, which is not enough for reliable ignition of the air-fuel mixture. Such a spark plug is immediately visible, since with each unsuccessful attempt to start the engine, it is flooded. Turn it out - if it is wet, then there is no spark, or it is too weak.

Here is what in the aggregate can give the correct cleaning of spark plugs (in fact, as well as buying new ones):

  • facilitating the start of a cold engine;
  • idling stabilization;
  • elimination of failures;
  • increase in power;
  • reduction in fuel consumption;
  • reduction of harmful emissions into the atmosphere.

It can also be added that, due to a poorly functioning spark plug, parts such as the piston, rings, cylinder, valves and their seats become overgrown with soot at an accelerated pace.

Should I clean spark plugs often?

Sometimes it's easier to buy a set of new candles
Sometimes it's easier to buy a set of new spark plug

It is difficult to answer this question specifically, since the rate of fouling of spark plug with soot depends on a number of factors:

  • gasoline quality;
  • state of the cylinder-piston group;
  • oil quality (for two-stroke engines);
  • fuel octane;
  • spark plug age;
  • gap between the electrodes.

On a serviceable gasoline engine, good spark plugs can easily work for at least 25,000 km. If it is a gasoline scythe, a chainsaw, a sprayer and other tools that are operated in a gentle mode - at least 2 years. Poor quality spark plug do not go for a long time, and there is not much point in cleaning them. Before they are covered with soot, more often there is a breakdown, burning or melting of the electrodes.

These spark plugs can not be cleaned
These spark plugs can not be cleaned

If high-quality branded spark plugs are installed in the engine, then their resource is much higher than 25 thousand km or 2 years. It is not a sin to clean these every 10,000 km, or once a year. As practice shows, in such cases it is possible to extend the life of expensive spark plug by two to three times. And for owners with pure karma, they go up to serious engine wear.

So don't clean the spark plugs!

Rubbed the electrodes with sandpaper - the spark plug can be thrown away
Rubbed the electrodes with sandpaper - the spark plug can be thrown away

In order not to waste time on useless gestures, never try to clean spark plug at home using tools such as:

  • sandpaper;
  • file;
  • nail file for manicure;
  • aggressive chemicals.

Before cleaning spark plug from soot, there are three things to remember about them. Firstly, modern models have the thinnest coating on the electrodes, which is very desirable to keep. Secondly, the electrodes do not just initially have their own length and thickness. Thirdly, the surfaces between which the spark jumps must be as smooth as possible.

As for the use of aggressive chemicals, after it a film may remain on the electrodes, due to which the spark plug will not work normally even if it is clean. Some substances that do an excellent job with soot leave craters on the surface of the electrodes, which is also bad.

Roasting is one of the wrong ways to clean spark plugs with your own hands. In no case should the electrodes be heated on a gas stove, gas burner, lighter or other sources of open flame. With soot, this, of course, will help to cope. However, excessive heating will cause the metal to become soft, and the correct gap between the electrodes will no longer be maintained.

Roasting - no!
Roasting - no!

In general: we don’t tear, we don’t scrape, we don’t heat with fire and we don’t soak in means for cleaning pans and the like! By the way, soda, dimexide, acid solutions (for example, an electrolyte with a battery) are also garbage.

Gentle and effective spark plug cleaning

If you want to clean the spark plug from soot so that they also work later, then prepare:

  1. Glass container (glass, jar).
  2. Table vinegar 9%.
  3. Good dish detergent (cheap ones also work, but weaker and longer).
  4. An old toothbrush.
  5. Rags without lint.

Directly the process of cleaning spark plug begins with their eversion. First of all, visually inspect the electrodes for irreparable defects such as burning or melting. If you see this, throw it away and forget it. If the electrodes are intact, but just in a layer of soot, carefully clean off its loose layer with something plastic or wooden (a toothpick, but not a needle). This will speed up the next process.

Instead of vinegar, you can use a solution of citric acid
Instead of vinegar, you can use a solution of citric acid

Now place the prepared spark plugs in a glass container and completely fill them with vinegar. It is important that it is exactly a 9% solution, and not a concentrate. You will immediately see how the process begins. Bubbles will appear and the liquid will become dirty. Leave the spark plug to sour in the vinegar until the reaction stops. To speed things up, periodically shake the container.

From the lessons of school chemistry, everyone remembers that almost any reaction can be accelerated by heating. Heat spark plug soaked in vinegar in a water bath. The reaction will intensify before our eyes, and the soot will dissolve much faster. Attention: do not use a microwave oven for heating!

When the reaction in vinegar stops, take a toothbrush and clean the electrodes directly in the same solution as far as possible. A toothpick at this stage is also useful if the soot is particularly resistant.

Next, remove the spark plug from the vinegar and rinse them with running warm water. Then fill a container with clean warm water and add dishwashing detergent to it. More. Rinse the spark plug, using the toothbrush again.

After cleaning the spark plug, rinse thoroughly with clean water, wipe with a rag and dry. When dry, do not forget to check and correct, if necessary, the gap between the electrodes.

VIDEO: cleaning spark plugs


Cleaning spark plug is not a useless event if they are intact, not broken, but covered with soot. Don't bother with cheap ones - throw them away and buy new ones. If the spark plug are potentially good, clean them of carbon deposits at least once a year or every 10,000 km in the manner described here. Do not use abrasive, metal objects and vigorous chemicals.