How to stop the piston in a chainsaw. Malfunctions of the chainsaw cylinder-piston group

Fotoreport: Installation of the piston on a motorcycle “Izh”, “Muravey”, “Voskhod

Breakdowns can be planned and emergency. Scheduled failure depends on the manufacturer, materials of manufacture of the group, and intensity of use. It is common to calculate the life of a chainsaw in motor-hours. After the specified number of hours you should send the tool in for preventive maintenance of the engine.

  • operation with high loads which are not comparable to the power of the tool;
  • Lack of normal maintenance, which leads to dry operation of the motor and increased wear;
  • the use of low-quality fuel, which does not give stable operation of the engine;
  • the age of the saw, despite the low intensity of operation.

Every time you start up your tool, it puts a certain amount of stress on the piston and cylinder. the number of starts also influences the service life. If you notice extraneous sounds from the motor, reduced power, increased consumption, it is time to give the equipment for preventive maintenance to the service center.

When Chain Saw Carburetor Adjustment is Necessary

Adjusting the carburetor of a Partner P350S chainsaw is necessary only when there are obvious problems with the hardware. In its initial state after purchase, no tuning is necessary. The cause of carburetor problems can be temperature fluctuations during storage of the saw or an improperly selected fuel mixture. If changing the fuel does not help and the saw squeals or produces smoke from the exhaust, adjustment is still necessary. In ideal conditions, namely in a service center, it is much easier to do so because they have special equipment, namely carburetor stroke counters and tachometers. If such tools are not found at hand, you need to apply all your skills and experience to achieve the desired result.

The need for adjustment of the carburetor of the Partner-350 chainsaw can also be caused by mechanical problems. For example, strong vibrations can damage the protective cap. The result is that the carburetor’s screws become loose.

Another possible cause is engine piston wear and tear. In such a case, the adjustment of the carburetor allows you to use the unit for some time, but to fix the problem requires the replacement of the worn part. Another cause may be a clogging caused by using low-quality fuel. Such problems can be caused by scale buildup and damage to the filter. In order to eliminate the resulting malfunctions, the carburettor has to be disassembled, flushed and then repaired.

Purpose and principle of operation

The ignition coil enables the low-voltage pulse from the power supply to be converted into a high-voltage pulse, without which no spark can be produced. It can have from 1 to 3 lobes in the electrical breakdown gate. Depending on the specifications of the power plant, the breakdown gap may be in the range of 0.4-1.1 mm. In order to ensure reliable ignition, the voltage of the electrical impulse must be at least 10 kV. It must be remembered that there may be a voltage drop in the conductors and therefore the coil must produce a pulse of 12 to 20 kV.

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This strain can pose a serious danger to people and is especially true for those who suffer from various heart ailments. When checking a faulty coil, you must exercise the utmost caution, because even standard rubber gloves can not guarantee complete safety. The principle of operation of this element resembles an autotransformer. Copper wire coated with insulating varnish is used to create the primary winding. The number of windings is usually 100 to 200. The secondary winding has a thinner conductor, but has 2000-3000 turns.

During the operation of the power plant, a cam mechanism located in the tumbler rotates. The main task of this element is to open the contacts. When a short circuit occurs, a high current flows through the primary winding. This induces an induction in the secondary winding and a high voltage impulse is transmitted to the spark plug gap.

This ignition circuit has been used in automobiles for a long time. Its main disadvantage is the burning of the contacts due to the high current flowing through them. Often the owners of vehicles have supplemented the factory circuit with a simple electronic amplifier.

Today the situation has changed and manufacturers are actively using more reliable devices instead of breakers, such as a Hall sensor. If the user needs to know how to check the ignition coil of a chainsaw with a multimeter, this procedure is carried out similarly to the one for testing car candles.

How to change the piston on a STIHL 180 chain saw

If it is necessary to replace the old piston and install a new one, it is necessary to know how to do it correctly and follow a certain algorithm of actions. Also needed are a small slotted screwdriver, a special STIHL combination wrench, a power screwdriver, a hammer, a soft material hammer, a compressor and a STIHL piston stop.

Before beginning work on replacing the piston or piston assembly, the chainsaw must be cleaned as thoroughly as possible. Next, the work is carried out according to the following algorithm:

  • Remove the top cover from the saw and unscrew the spark plug.
  • Remove side cover.
  • Use a power screwdriver to remove the stops from the chain saw’s shock absorbers, then detach its handle from the housing.
  • Next, it is necessary to remove the drive sprocket and the starter.
  • Put the piston stopper in the spark plug hole and undo the flywheel and clutch mounting nut.
  • Remove the flywheel, clutch and oil pump worm drive mechanism behind the clutch.
  • Remove the two screws that fix the carburetor and the air filter. Remove the filter, engine lever and STIHL carburettor.
  • Remove the ignition coil and muffler.

After all these operations are done, it is necessary to clean the saw from dirt, then turn it over with the bottom up and unscrew the four screws for fixing the engine to the chainsaw body. Having unscrewed the screws, the engine is separated from the housing and cleaned once more.

With the engine removed, unscrew and remove the sump, after which the piston and crankshaft assembly is removed from the engine.

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When removing the piston from the cylinder, remember how it was positioned relative to the cylinder.

Then the piston pin retaining rings are removed with a small screwdriver and the crankshaft is separated from the piston.

In the case where only the piston needs to be replaced, you can install it on the crankshaft, and then mount the piston pin retaining rings, while positioning them in such a way that the place of the retaining ring breakage, pointing downwards. This is to ensure that the retaining rings do not come out of their sockets accidentally when the engine is running (see STIHL manual). Then the compression rings are fitted, the cylinder is lubricated with engine oil and the engine is reassembled.

When installing the piston in the cylinder, extreme care must be taken to prevent excessive wear and tear on the cylinder. к. Compression rings are brittle and break easily.

The crankcase is fitted to the engine, a sealant is used as a gasket, and then the four fastening screws are fastened and tightened crosswise. Then the engine is mounted on the chain saw. The subsequent reassembly is done in reverse order of disassembly.

When the piston needs to be replaced

There are many reasons for replacing the piston and the entire piston assembly, but they can all be subdivided into natural causes and those resulting from improper use. Natural. wear and tear from continuous use of the STIHL STIHL 180 chain saw. There are many more artificial ones, for example:

Have the cylinder head checked when the STIHL mc 180 180 suddenly loses power or fails to start and the starter does not turn. If the starter motor turns but the saw does not start and the spark and fuel are still in the cylinder, check the compression in the engine.

Chain oil rule.

Use special chain oil to lubricate the tire and the chain. It is the adhesive oil that has the property of stickiness and stays on the tire during work. Use of other oils is ineffective because they will fly off when the cutting attachment is in operation and do not have the necessary adhesiveness. Furthermore, the use of other oils can cause the oil pump to malfunction.

Remember the rules if you want your tire and chain to last longer:

(a) Only use a special adhesive oil of high quality;

b) always check the oil level in the oil tank so you don’t forget to fill it first and the fuel mixture after it;

c) if the chainsaw has an oil feed adjustment, then in cold weather, the feed should be made as much as possible.

How to change the piston on a STIHL 180 chain saw

If it is necessary to replace the old piston and install a new one, you need to know how to do it correctly and follow a certain algorithm of actions. Also need a small slotted screwdriver, a special STIHL combination wrench, a power screwdriver, a hammer, a soft hammer, a compressor, and a STIHL piston lock.

Beginning the work on the replacement of the piston or piston group assembly, the chainsaw must be cleaned as thoroughly as possible from contamination. Next, the work is carried out according to the following algorithm:

  • The top cover is removed from the saw and the spark plug is unscrewed.
  • Remove the side cover.
  • Using a power screwdriver, remove the stoppers from the chainsaw shock absorbers, after which its handle is disconnected from the body.
  • Next, it is necessary to remove the drive sprocket and the starter.
  • Check that the oil level is within tolerance and the oil level is within tolerance.
  • Remove the flywheel, the clutch and the oil pump worm drive mechanism behind the clutch.
  • Remove the two screws that secure the carburetor and air filter. Remove filter, engine lever and STIHL carburetor.
  • Remove ignition coil and muffler.
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After all these operations it is necessary to clean the saw from dirt, then to turn it upside down and unscrew the four screws fastening the engine to the chainsaw body. After removing the screws, the engine is separated from the housing and cleaned again.

With the engine removed, unscrew and remove the pan, after which the piston and crankshaft are removed from the engine.

When removing the piston from the cylinder, note its position in relation to the cylinder.

Next, using a small screwdriver, the piston pin retaining rings are removed, and the crankshaft is disconnected from the piston.

In the case where only the piston needs to be replaced, you can install it on the crankshaft, then mount the piston pin retaining rings, while positioning them so that the place where the retaining ring breaks, pointing down. This is to ensure that the retaining ring does not pop out by itself when the engine is running (according to STIHL manufacturer’s instructions). After that, the compression rings are installed, the cylinder is lubricated with engine oil, and the engine is assembled.

The piston should be inserted into the cylinder with extreme care. к. Compression rings are brittle and break easily.

The crankcase is mounted on the engine, a sealant is used as a gasket, then the four fixing screws are mounted and tightened crosswise. Next, the engine is mounted on the chainsaw body. The subsequent assembly is performed in the reverse order of disassembly.

Assembly Partner 350

In order to properly assemble the Partner 350, you must install all elements in reverse order of removal.

If this is the first time you have your Partner 350 chainsaw repaired, stack the parts in the same order that you removed them. This prevents you from getting confused and forgetting to install a node.

An important feature of the assembly of the engine chainsaw Partner 350 is that the crankcase cover is installed without a gasket. Red sealant is used instead and a thin layer is applied to the crankcase mounting area. Before you apply sealant, you need to degrease the crankcase cover and the place where it is installed, for better adhesion of the sealant.

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