HOME > Disassembly Assembly Maintenance and Failure Analysis of Spark Plugs of Chainsaw

Disassembly Assembly Maintenance and Failure Analysis of Spark Plugs of Chainsaw

source : UANBUY    Author :    Time : 20-10-2020

The structure of the chain saw spark plug is the same as the commonly used automobile spark plug. According to the material, the whole is divided into two parts: the insulator and the metal shell; according to the structure, it is divided into three parts, namely the central electrode, the steel body and the electrode, and the insulating ceramic core. The upper part of the steel body is made of hexagon for easy disassembly and assembly of the wrench, and the lower part has threads which can be screwed into the cylinder head. The metal shell has threads for screwing into the cylinder; the shell is equipped with an insulator, which penetrates a center electrode, and there is a wiring nut on the upper end of the center electrode to connect the high-voltage wire from the distribution board; The lower end surface is welded with a grounding electrode, and there is a gap of 0.6-1.0 mm between the center electrode and the grounding electrode. High-voltage electricity passing through this gap will burst into the ground and spark to ignite the mixture.


Chain saw spark plug function



The spark plug of the chain saw is generally installed on the top of the middle cylinder, conducts the current generated from the high pressure package, and conducts the combustion of the mixed vapor in the cylinder, which plays an important role in the operation of the engine; it depends on the gas (air) under the influence of certain factors. The gas discharge principle that can dissociate and become a conductor uses the high pulse voltage generated by the gasoline engine ignition system to break down the gap formed between the center electrode and the side electrode of the spark plug. When the gap is broken down, due to ions and electrons The high-speed movement of the gas forms a high-temperature and hot ionization channel, and an arc spark is generated, which ignites the compressed combustible mixed gas in the combustion chamber of the gasoline engine, and the mixed gas burns and expands to complete the work stroke. The spark plug is the terminal of the circuit, and it bears a large amount of work. It is one of the main functions of the chain saw accessories that cannot be underestimated.


Disassembly, assembly and maintenance of spark plug of chainsaw


There is a hexagon socket nut at the rib of the spark plug of the chain saw and the insulating ceramics, which can be disassembled and assembled with a 19MM curved handle sleeve. Most chain saws are equipped with a T-shaped three-purpose wrench; because the chain saw uses mixed gasoline, the spark plug will be more Other spark plugs powered by pure gasoline are more likely to accumulate carbon. The spark plug of the chain saw should be maintained frequently to ensure that the chain saw works normally; if the spark plug of the chain saw has carbon accumulation, the spark plug should be immersed in gasoline and cleaned with a brush, or use sandpaper Or use a hard metal object to scrape off the carbon deposits on the electrode. Do not grill directly with fire. Although this looks like it can remove the carbon deposits, long-term direct grilling will cause problems with other parts of the chain saw spark plug and reduce the service life of the spark plug. .


It's easy to remove the spark plug. Just use a "spark plug socket" wrench. One thing is very important when installing. Do not screw the spark plug too tightly. Too tight can damage the threads on the cylinder head, especially the aluminum cylinder head. When installing, hold the spark plug sleeve first, tighten the spark plug, and then use a socket wrench to tighten 1/4 turn is enough. If the spark plug is not equipped with a washer but has a tapered mounting seat type, because the steel body of the spark plug directly touches the cylinder body, it can only be screwed in 1/16 turn with a wrench after the hand is tightened to prevent damage to the cylinder body. hurt.


The spark plug gap and the number of poles of the chainsaw


There is only a 0.6-1.0 mm gap between the center electrode of the spark plug of the chain saw and the ground electrode. Although the more ground electrodes, the wider the conductive contact surface, but because the carbon deposit of the chain saw is relatively uniform, the number of poles will vary. There is a certain difference, but it is almost negligible. In recent years, spark plugs with pole number as a selling point have appeared in China, which can be selected appropriately.



The common symptoms are sudden death and flameout after working for a period of time, and then it can't be pulled, and it takes a while to pull the fire. This happens again after working for a period of time, and it is more frequent when the weather is hot. This is a common situation in which the chainsaw stalls at high temperatures. What should we do if we encounter this situation? First of all, we have to find out the reasons. The usual reasons and solutions are as follows:


1. Ventilation problems. Mainly because the crankcase and plastic parts are not well ventilated, resulting in poor ventilation of the carburetor parts and high temperature stalls. Solution: ventilation, such as adding an air shroud at the magnetic flywheel or opening the channel between the magnetic flywheel and the carburetor on the crankcase, increasing the ventilation, or replacing the top cover and air filter of the case with better ventilation Cover kit.


2. Poor exhaust of muffler leads to high temperature. Solution: Clear the muffler or replace the muffler with a larger exhaust hole. (Note: A large number of holes does not necessarily mean faster rows. Double-hole large holes on the market will be better than three-hole small holes).


3. The carburetor has low temperature resistance. Solution: add heat insulation paper pad, ventilate, clean or replace the carburetor.


4. The coil/high voltage package is not resistant to high temperature. Solution: Replace directly.


5. The three parts of the cylinder: the material of at least one of the three parts of the cylinder, piston and piston ring is not good. Solution: Replace the chainsaw cylinder.


6. The oil seal and the negative pressure pipe (balanced air pipe) are not resistant to high temperature, which shows air leakage when the temperature is high. Solution: Replace the oil seal and negative pressure pipe (balanced air pipe) with good quality.



Chainsaw is one of the most widely used and most frequently used power tools among many garden machine products. Because it has very sharp teeth and is used for cutting wood at high speeds, strict safety precautions must be taken when using it. Any irregular operation and untimely maintenance will cause certain safety hazards, and users should pay attention to it.


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