- Nov 14, 2018 -
Maintenance and failure analysis of saw spark plug
The fuel saw spark plug is the same as the commonly used automobile spark plug, and the whole is composed of insulator and metal shell.
According to the structure, it is divided into three parts, namely the central electrode, the steel body and the bromide electrode, and the insulating porcelain core. The upper part of the steel body is made into hexagonal so that the spanner can be disassembled and assembled, and the lower part has screw teeth, which can be turned into the cylinder head.
The metal shell has threads for screwing into the cylinder;
There is an insulator inside the shell, which is connected with a central electrode, and a connecting nut on the upper end of the central electrode, connecting the high-voltage wire coming from the distributor.
There is a ground electrode welded on the lower end of the shell, and a gap of 0.6-1.0mm is between the center electrode and the ground electrode, through which a spark will be emitted to ignite the mixture.
Oil saw spark plug function
The oil saw spark plug is usually installed on the top of the middle cylinder, which leads the current generated from the high pressure package and plays an important role in the work of the engine in the cylinder.
It according to the gas (air) under the influence of some factors can happen disassociation and become conductive principle of gas discharge by using high voltage pulse generated by gasoline engine ignition system to breakdown the spark plug center of the space between the electrode and side electrode, when the gap was breakdown, because of the high speed movement of ions and electrons to form a high temperature hot ionization channels, and generate spark, arc and ignite gasoline engine combustion chamber of the compressed combustible mixture gas, mixture combustion, complete the power stroke.
Spark plug belongs to the terminal of the circuit, bearing a large workload, function of the main function of the saw accessories should not be overlooked.
Maintenance and disassembly of spark plug of oil saw
There is a hexagonal rotator on the spark saws and insulating ceramics that can be disassembled with a 19MM curved handle sleeve.
Due to the use of mixed gasoline, the spark plug is more likely to accumulate carbon than other spark plugs powered by pure gasoline.
Chain saw the spark plug if carbon deposition, should put the spark plug into gasoline with a clean brush MAO carbon deposit, or with sand paper or a hard metal scrape off the carbon electrodes, avoid by all means directly with fire barbecue, though it looks like can remove carbon deposition, but barbecue directly with long time can cause chain saw the spark plug other parts out of the question, to reduce the service life of the spark plug.
It is very easy to remove the spark plug simply by using the "spark plug sleeve" wrench, when installed, it is very important to do not screw the spark plug too tight, too tight easy to hurt the screw on the cylinder cover, especially the aluminum cylinder cover.
Hold the spark plug sleeve in your hand and tighten the spark plug. Use a socket wrench to tighten 1/4 turn.
If the spark plug is not equipped with a gasket, but with a cone mounting type, the spark plug steel body directly touches the cylinder body, so the hand after twisting can only be used to screw in 1/16 turn to avoid injury to the cylinder.
Problem of spark plug gap and number of poles of oil saw
Chain saw the spark plug center between the electrode and the grounding electrode periods of 0.6 1.0 mm, while the grounding electrodes, the more conductive contact surface will be more widely, but because of the carbon chain saw is relatively uniform, so although the number of how many there will be a certain difference, but almost negligible, but in recent years the number of domestic appeared to spark plug as a selling point, can choose appropriate.
A common symptom is that after working for a period of time, the fire stops suddenly, and then the fire stops. It takes a while for the fire to catch on. After working for a period of time, this happens again.
This is a common situation of oil saw turning off at high temperature. What should we do in this situation?
First, we need to find out the reasons. The usual reasons and solutions are as follows:
1. Ventilation problem.
It is mainly caused by poor ventilation of crankcase and plastic parts, resulting in high temperature quenching caused by poor ventilation of carburetor parts.
Solution: ventilation, such as adding an air deflector at the magnetic flywheel or opening the passage between the magnetic flywheel and carburetor on the crankcase, increasing ventilation, or replacing the better ventilated upper cover and empty filter cover kit.
2. Poor exhaust of muffler causes high temperature.
Solution: clearing the muffler or replacing the muffler with a larger vent.
(note: the number of holes is not necessarily fast, and the large holes with two holes are better than those with three holes in the market).
3. Low temperature resistance of carburetor.
Solution: add insulated paper pads, ventilate, clean or replace carburetors.
4. Coil/high pressure package not resistant to high temperature.
Solution: replace directly.
5. Cylinder three parts: at least one of the three parts of cylinder, piston and piston ring cannot be made of material.
Solution: replace the oil saw cylinder.
6. Oil seal and negative pressure pipe (balance pipe) are not resistant to high temperature, showing air leakage at high temperature.
Solution: replace good quality oil seal and negative pressure pipe (balance pipe).
Oil saw is one of the most widely used and most frequently used power tools in many industrial machinery products.
As it has very sharp serrated teeth and is used to cut wood at high speed, strict safety precautions should be taken when using it.
Any not standard operation, not timely maintenance, will form a certain security risks, users need to pay attention.