Spark Plug Spark Plugs

A chainsaw consists of many components important for the functioning of the system, including a spark plug. This small part needs to be replaced periodically. You can replace it yourself. Usually it’s enough to use a universal instruction that is suitable for all models of the power unit. But before you look for instructions, you will have to purchase a new spare part. Don’t know which candle to choose for a chainsaw? This and other information is available in this article.

Spark Plug Spark Plugs

What is a spark plug and why change it?

The part itself is responsible for igniting the air-fuel mixture. It is necessary to change the spark plug when there are problems on the part of the motor (it works, but is unstable), this procedure is also necessary when the tool just stops turning on.

Candles for Husqvarna chainsaws and for power units of other manufacturers are also recommended to be replaced every hundred hours of operation of the chainsaw. This is a consumable spare part that wears out due to:

  • low quality oil applications (electrons, side and center, covered with black soot);
  • a poorly tuned carburetor or a broken start-up system (a candle due to this will be filled with a fuel mixture);
  • the carburetor is out of order (no spark will come to the spark plug, which causes a problematic start of the tool engine).

Varieties of candles

There is no such thing as universal candles. They differ among themselves in a number of parameters:

  • body geometry;
  • thread diameter;
  • thread length (shirt length, as the craftsmen call it).

There are concepts such as “warm” and “cold” candle. A large glow number indicates that the candle is cold (it is not so effective to absorb heat that comes from the combustion chamber), a low glow number indicates that the candle is hot.

When replacing a candle, purchasing a new spare part, it is easiest to look for one that matches the parameters declared by the manufacturer (these parameters are indicated in the instructions that accompany the tool). If for some reason you do not have access to the data, conduct a visual inspection of the candle, remove the parameters, including the number (glow) indicated on it.

At the moment in the modern market you can find candles produced under the brand Champion, Stihl, Brisk, Bosch, Oregon, NGK, there are also certain options that are suitable for models produced by Partner, Husqvarna, Stig, AL-KO, Oleo-mac , Wolf Garten, Mc Culloch, etc. At the same time, do not forget that you need to know the clearance on the chainsaw candle.

Video: Spark Plug Spark Plugs


To remove the necessary parameters, you need to dismantle this element. It is easy to unscrew it with a candle key, which as standard is part of the power unit.

Candle inspection, problem identification

Before you put a new candle, make sure that the problem in the operation of the device is associated with this particular part. To get started, take a look at the thermal cone of insulation and electrodes. Their appearance will tell you about the operation of the engine and there are a lot of qualitative indicators of the fuel mixture.

If you changed the spark plug recently, inspect the above units for serviceability, check if the spark plug clearance on the chainsaw is set correctly. A careful inspection of the main components of the unit will allow you to extend the operational life of the tool and will give you the opportunity to save personal funds.

Perhaps the last time you changed the spark plug, you chose the wrong one for your saw. If the case of this part is covered with an oil dark layer, this indicates that the candle is too cold for your tool (not suitable for the engine).

Important! Sometimes this same “symptom” indicates an overestimated oil level of the crater, worn piston and cylinder rings, as well as an excessive amount of oil in the mixture that you use for the 2-stroke engine.

The deposit is dark, but dry may indicate a cold candle, which is not suitable for the engine of your saw. The same “symptom” also manifests itself during intensive use of the device at idle or at low speeds in operating mode.

If the chainsaw is bad to start, it is possible to fill the candle on the chainsaw. You can solve the problem by reading the article here.

And how to understand that the selected spark plug for the chainsaw engine is too hot? The cone of the part will be dry, almost white, without a hint of traces of oil (only occasionally traces of reflow can be noticeable). This may indicate that the candle was installed incorrectly.

If the candle is selected correctly (and installed correctly) there will be no traces of reflow or carbon deposits on its cone. Plaque brown or gray (light shades) can be considered the norm, which indicates that this unit operates without problems.

How to adjust the spark plug clearance?

Ideally, this is done using a template that you can choose from:

  • to get;
  • to make yourself using thick plastic.

Ideally, the gap between the electrodes should be about 0.5 mm. Try to tighten the fasteners before removing the template, but do not overdo it so that you do not accidentally break the fragile parts located with this assembly.

How to clean candles?

Pay attention to candle cleaning (an important stage of tool maintenance ”, as well as clearance correction). With intensive use of the unit, this procedure is carried out weekly. In another case, it is enough twice a year (before the start of winter operation and the summer season).

Candles for the Partner chainsaw, as well as candles, Champion, parts of other models and brands of tools, are ideally cleaned chemically. They are degreased with a solvent or acetone, and then dried (in the summer in the sun, and alternatively on a stove burner). Then the candle is treated with a 20% solution of ammonium acetate (hot liquid). If necessary, the candle is cleaned using a nylon or metal brush. Finally, the part is washed and dried.