Chainsaw swimming on hot. The design and principle of the functioning of the carburetor of the chainsaw

Why the chainsaw is sneezed

Although motorcycles are a simple device, from time to time in its work, problems arise, which can only be eliminated by disassembling. The following malfunctions can be given as examples:

chainsaw, principle, functioning, carburetor
  • a chainsaw is not gaining momentum;
  • chainsaws stops functioning in the cut;
  • The chainsaw is started and stalling;
  • a chainsaw loses its power;
  • Basil stalls when pressed.

Most often, the malfunctions are associated with interruptions in the functioning of the motor, as well as with the problems of other systems and nodes. The correct handling of this technique is of great importance. When fulfilling all the rules for using a high probability problem lies in the most obvious. When searching for the causes of problems, it is advisable to start by checking the simplest part of the motorcycle and end the most difficult.

Checking the main chainsaw systems

If the chainsaw refuses to work normally, it is necessary to make sure that all the conditions required for its normal functioning are provided:

Then you need to sequentially check the functioning of all its elements. First you need to check the fuel tank. If the cause is not in volume and not as fuel, then the ignition candles may be a probable cause of a malfunction. The gap in the candle should not exceed 0.5 millimeters. If he is too small, this means that the Nar was deposited on the candles. In this case, the candles should be removed, cleaned them, and then install them in place and try to start a chainsaw. In addition, it is advisable to completely change candles from time to time to new ones, even if they are in good condition.

Then you need to check the condition of the fuel filter and carburetor. Independent cleaning of the fuel filter is a simple task, but the repair of the carburetor is best entrusted to specialists.

Why is the chainsaw stall under load

In some cases, chainsaws are unable to work normally with a load and just stalls. A common cause of this behavior is the wrong adjustment of the carburetor, or air leaks through the crankshaft oil seals or a carburetor laying. And such behavior can also occur due to the leakage of the carburetor.

Diagnose the cause and eliminate the fact that the chainsaw is started and stall under load, best in the service center, t. to. A special tool is needed to check the tightness of the carburetor and the engine crankcase.

The saw unable to work under load will also uncertainly hold the idle speed. They will “swim”. Diagnostics begin with verification for the tightness of the crankcase and carburetor. If the air leaks are found through the crankshaft oil seals, they must be replaced. If an air leak is detected in a carburetor, it is possible to eliminate the cause by installing a repair set of gaskets.

Only after the above actions did not give the result and the engine crankcase with the carburetor is sealed, you can proceed to adjust the carburetor.

The reason for this algorithm is as follows, if the air leakage from the crankcase is not eliminated, but the carburetor was simply adjusted to the normal operation of the engine, then the fuel mixture will contain a larger amount of fuel than it is required with a tight crankcase, which in turn will significantly increase its flow rate. Also, most likely, soar will appear in the engine, which will also adversely affect the further work of the chainsaw.

In some models of chainsaws, to ensure the operation of the fuel pump, special hoses are installed, which transmit the air pulse from the engine crankcase to the fuel pump of the carburetor. If this hose is overwhelmed, the saw will work unevenly at idle and will not work under load at all.

Husqvarna 137 and Husqvarna 142 household owners with any deviations of the engine from the norm, first of all, check the pulse hose, t. to. This is considered the most common cause of the breakdown of these chainsaws.

Why does the chainsaw not gain momentum and stalls

If the chainsaws a minute after the start is not able to gain momentum or stalls when pressing the gas trigger, most likely, the carburetor or engine crankcase is leaky. As in the previous case, the problem can be solved by checking for tightness and adjusting the carburetor.

If the chainsaw does not gain momentum and stalls after it worked normally for about 5 minutes, the reason may consist in a defective fuel tank saep. The vacuum created in the fuel tank during the operation of the tool does not allow the engine to receive the required amount of fuel for its normal operation, and for this reason it will be unable to gain momentum or stall. At the same time, if you stop the tool, open and close the lid of the fuel tank and start the chainsaw again, the tool will again work normally for about five minutes, after which it will stop gaining speed or staller.

The reason that the chainsaws are not gaining momentum may be an excessive incident in the muffler, which complicates the production of exhaust gases, thereby reducing the power and engine speed.

If desired, the need to check the tightness of the crankcase, but the absence of a special tool, you can use the following verification methodology.

Carter testing algorithm for tightness

  • Remove the side cover and tire from the chainsaw.
  • Unscrew the spark plug and lay the lace with nodules into the cylinder through the candle hole, thereby stagging the movement of the piston and crankshaft.
  • As a lace with nodules, you can use the old cord from the starter, imposing nodules on it after 3-5 cm.
  • Spin the leading star of the chainsaw.
  • Remove the lid of the oil pump and the pump itself.
  • Remove the starter from the chainsaw.
  • Spin and remove the flywheel.
  • Remove the carburetor.
  • Using a syringe, through a hole under the carburetor in the cylinder, pour gasoline into the crankcase, while watching the crankshaft oil seals. If gasoline is leaking through them, then the seals are unusable and they must be replaced with new.
  • It is better to entrust the installation of oil seals to professionals.

An indirect sign of crankcase leakage is oil sinks in the seamstress area.

Basil starts and stalls. the reason

If the chainsaw is started and stalling at the first attempts to do the work, then the reason may consist of problems with the brake of the chain or in its jamming due to lack of lubrication. In this case, the level of oil is measured. If the lubricant volume is sufficient, then the reason may be in the tube that leads it to the lubricant mechanism.

Another reason may be a carburetor breakdown. If he needs only adjustment, it can be done independently in accordance with the instructions. If the carburetor needs to be cleaned or repair, then you can not do without the help of professionals.

Another possible cause of this malfunction is a low fuel level in the tank. In this case, the motorcycle is stalling when tilted, since the remainder of the fuel mixture is in the part of the tank, the opposite of the place where the suction tube is located.

Why the chainsaw stalls when heated

It often happens that the motorcycle starts up on the cold, but stalls in the process of heating. This behavior of the tool can be caused by the following reasons:

  • The carburetor is incorrectly configured. This problem can be identified by the way the device is launched on a cold. If it is carried out without closing the air damper, and the engine is launched without a preliminary flash, this means that after heating the motor, the fuel floods the candle. The solution to this problem is to adjust the carburetor. Details about carburetor adjustment
  • Coil malfunction (ignition module). This problem can be identified by sequentially checking the spark first on the cold, and then on a hot motor. If there is no spark on the hot motor, then you need to replace the ignition coil.
  • Falf in the spark plug. In this situation, as with the malfunction of the ignition module, the spark disappears when the motor is heated. It is necessary to replace the candle with a new one, and if this did not lead to the solution of the problem, then the ignition module and the distance between it and the flywheel should be checked.


The adjustment of the StiHL chainsaw carburetor will be required when the property of the fuel, height above sea level, is busy, the stihl chainsaws are operated, also when atmospheric pressure, temperature and humidity change. Setting up the chainsaw carburetor allows you to achieve good performance of the chainsaw when the external operating criterion deteriorates. Also, adjustment of the gasopyle carburetor allows you to prevent oil starvation and a breakdown of the motor due to insufficient lubrication entering the cylinder with depleted fuel consistency.

STIHL adjustment of idle video.

Tip: To check the density of the motor, it is amazing to use a special device, t.e. A special pump with a manometer. At first, you need to remove the carburetor on the chainsaw, and install a sealed plate plug with a flanet to connect the hose from the pump on the cylinder inlet window. The spark plug for density also has an option to be planted on a sealant. You also need to remove the silencer, and install a sealed plate with a rubber gasket on the output window of the cylinder. Then you need to put the piston in the upper dead point and connect the hose from the pump to the flanet. Next, you need to pump up the air up to 0.9 atm into the engine. and look at the arrow of the manometer. if it stands in one place, means the piston engine is sealed. Then we release the air, switch the device (pump) and begin to pump out air from the cylinder, creating a vacuum in the engine with the testimony of the manometer in.0.5 atm. We look at the arrow of the manometer. if it stands at the workplace, means through the oil seals in other words of other seals in the engine there is no air suction (which exacerbates the operation of the chainsaw does not make it possible to correctly adjust the carburetor of the chainsaw). In such a macar, we check the engine for air leaks and compression.

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How to assemble

After the implementation of all repair work, the quality of reverse assembly is of great importance. The improper location of the part can lead to a breakdown of technology and be unsafe for a person.

  • The most responsible part is the assembly of the saw headset. It is better to produce it in protective gloves to avoid cuts from stars. When setting the chain on the tire, pay attention to the direction of the edge of the teeth. She should go forward, at the top of the tire. Place the mechanism on the leading star. Return the clutch cover, tighten the nuts.
  • To tension the chain use a special key. The quality of this work affects the safety and effectiveness of the operation of equipment in the future. The poorly stretched chain will fly off, and a tight tension threatens with quick wear. The chain can be raised above the tire no more than 1 cm. Check rotation and tighten the nuts.

Any repair work of complex equipment should be carried out carefully. Use the original spare components better for this. Other options may negatively affect the service life of the device. If you are not sure that you can do it yourself, it is better to contact a specialized workshop.

This is especially applicable to the expensive professional technique. Incorrectly repaired can lead to failure of the entire mechanism. To prevent breakdowns, try to comply with the requirements of the instructions for work, serve the tool in time, monitor the mechanisms, use high.quality oil and fuel, replace fast.significant elements.

The setting of the saw carburetor can be studied by the video presented below. In this video, the master shows how the phased adjustment of Champion chainsaw is performed, Chinese.made, without the use of a tachometer. Conducts after adjusting verification in various modes.

The adjustment of the chainsaw carburetor, although it looks simple, it requires an attentive and responsible approach. In the article, the entire setting process is described in detail, but if there is no experience of adjusting the chainsaws, it will be worth it to contact a specialized service for repairing a construction tool, this will help save time, nerves and means.

chainsaw, principle, functioning, carburetor

The most common reasons

The chainsaw is considered a fairly simple and tool, but it can suddenly stop working. The reasons why the chainsaws are poorly started and stalling can be different: from poor.quality gasoline to serious malfunctions. Most often, it is possible to find the reason on your own, but in some cases you will have to contact the master. It is important to remember that it is impossible to work with a faulty chainsaw.

33cc Homelite chainsaw won’t stay running.

Fuel mixture

The most common reason for the refusal is the problem with gasoline or oil. It is necessary to use the fuel of the brand recommended by the manufacturer. When choosing oil, it is worth choosing oils with special additives. Typically, manufacturers recommend choosing AI-92 gasoline and two-stroke oil.

The second reason is in quantity. If there is too little gasoline, the chainsaw will not start, if there is little oil, the tool canvas will jam, after which it will stop working.

In addition, it is important to observe the proportions of gasoline and oil. They are indicated in the instructions for the tool. Most often, 25 ml of oil is required per liter of gasoline.


The reason why the chainsaws are not gaining momentum and stalls is in a contaminated air filter. He does not allow air to the volume that is necessary for the tool for high.quality work. Initially, the carburetor is configured in such a way as to mix a certain amount of incoming air and gasoline. When the filter is polluted, the amount of incoming air decreases, and the amount of gasoline remains on the previous. The result is an enriched mixture.

The filter must also be changed depending on the time of the year:

  • In summer, a cotton filter is used in dry air;
  • The HD2 filter is used when working in winter or in dusty conditions, for example, when harvesting a large number of forests.

With contamination of the fuel filter, the situation is reverse: the amount of fuel decreases, the mixture becomes more poor. Uniform fuel supply is disturbed, and the chainsaw stalls when pressed on gas.

Spark plug

I figure out why the chainsaw stalls at idle, it is worth immediately checking the spark plug. It is an important part of the tool. There may be several problems with it:

  • It can be poured with oil or fuel during the launch process. This is especially common when inexperienced masters do not comply with the sequence of launch. You need to unscrew the candle and let it dry or screw it up.
  • The candle can be covered with a soil due to long-term work. To prevent this from happening, candles must be regularly cleaned with a metal brush or sandpaper with small grain. It is also worth changing candles regularly.
  • There may be problems with the tip of the candle. Check this is easy: you need to unscrew the candle and pull the launch cord. If a spark appears, then the candle and electronics are in order. If there is no spark, the problem may be associated with depressurization of tubes or with a suction of the fuel filter.
  • The problem may be associated with a disruption of the gap between the magneto and the ignition coil. The size of the clearance is indicated in the instructions for the tool, on average it is 0.5-0.65 mm. The problem may arise due to work in difficult conditions when the saw is subjected to shock.


If the chainsaw does not hold idle speed, it is worth checking the bacon. This is a small valve, a hole in the sawing machine, through which air passes. Thanks to this, a vacuum is not formed in the tank, and the tool works without interruptions. The saapun can be located in the tank lid or in the wall.

When clogging the cabin, a sparse atmosphere is created inside. Because of this, gasoline does not go to the carburetor. It happens that the primer (this is a pump for preliminary fuel supply) pumps a small amount of gasoline into the carburetor, and the chainsaw is started. But after gasoline in the carburetor ends, the tool stalls, because the clogged sapun does not allow fuel to go through.


If the chainsaw is stalling, most likely the problem is the carburetor. This part accounts for about half of all cases.

  • Nozzles, channels, filter, nozzles clogged. Often this is due to poor.quality fuel. The filter is not able to cleanse gasoline from impurities and garbage, which leads to buzzing jackets. Gasoline ceases to flow in the right amount, or even ceases to be supplied at all. At the same time, the saw loses greatly in power, soon ceases to work completely. To eliminate the problem, you will have to disassemble and clean the carburetor.
  • If the chainsaw stalls on the “hot”, it is worth checking if the rubber cuff was damaged in an accelerator pump. This leads to the receipt of additional air inside (“suction”), which is why the speed increases, and soon the tool stalls. The problem is solved by the replacement of the cuff. It happens that the replacement of the cuff does not solve the problem. the air continues to “suck”. If you determine where the air comes from, it does not work, you will have to replace all gaskets and seals.
  • The needle of the accelerating pump began to fall asleep. The reason may consist in wear or hit foreign objects inward. The saw will stop starting or begin to turn off during operation.
  • The check valve needle adjacent to the saddle. In this case, the chainsaws will begin to stall with an increase in the load, it will be bad and unstable, the candles will begin to fill. It will not work to fix the needle, it is better to replace the entire carburetor.

Also, the problem may be incorrectly adjusting the carburetor.

“S suck” air

This is another common reason, which is why the chainsaw stalls at idle. Excess air interferes with the work of the tool, it does not start or constantly stalls.

  • Fuel hoses. When using low.quality fuel, small cracks can form on them, they are easy to see during visual examination. It is also worth checking the fitness density: the hose should sit tight enough.
  • Basils. There are only two of them, they are attached to the crankshaft. ELks can wear out during operation or just from time to time. You can check the tightness using a compressor. To do this, you will need to close the input hole on the carburetor and the output on the muffler, unscrew the candle and supply air under pressure. If a hiss or pressure does not rise, then the seals should be replaced.
  • Gaskets. They can be damaged by poor.quality repair, during the assembly and disassembly of the tool, when installing.


Another reason for which the chainsaw is not gaining momentum and stalls is a muffler. It may appear on it over time. Its appearance is especially facilitated by poor.quality gasoline and oil, as well as the use of too much oil in the mixture or excess lubrication. Nar does not allow the worked out gas to go outside, which is why the saw overheats.

In the process, the chain can simply jam, after which the saw stalls. There may be several reasons:

In all cases, the tire of the chainsaw remains dry.

Cylinder.piston group (CPG)

This is the most unpleasant and expensive breakdown. Replacement of CPH at the cost of the cost of half the tool. It is best to take the saw to the service and not try to make it out on your own.

Carburetor adjustment on a chainsaw

How to adjust the carburetor on a chainsaw. And so we have three screws of carburetor adjustment. The screw H is responsible for the tenor circulation. this is the maximum revolution that develops the saw at maximum power. The screw l is responsible for low speeds, at idle saw, at low speeds. The screw t regulates the opening of the throttle, that is, it is the same damper that works when we press the gas handle.

That is, the screw T is responsible for us for the volume of air supply to the combustion room. The screw l is responsible for supplying fuel to the combustion chamber. The screw N is responsible for supplying fuel to the combustion chamber at high speeds.

In general, an uncomplicated scheme. Rotating the screw clockwise, we open the throttle and provide a larger amount of air that will enter the combustion room. And to the turnover, to close, we turn counterclockwise reducing the amount of air entering the combustion chamber.

This can be observed at idle when we begin to twist the screw to the right, the throttle. We turn the screw in the left side, counterclockwise the damper is completely blocked.

How to eliminate the malfunctions of the carburetor

The main malfunctions of the carburetor of the chainsaw can be as follows.

  • The engine starts with difficulty and stalls a few seconds after the start. Often the reason for this is the wrong setting of low speeds. The fuel-air mixture is poorly enriched. It is necessary to unscrew the “l” screw for half a turn, after which the setting should be completed by the “t” screw.
  • The engine power is significantly reduced during load. This means that the carburetor enriches the mixture with oxygen. Therefore, the screw “h” must be twisted a little, about 1/8 turnover. If after such actions the engine power is still insufficient, but there was a certain improvement in its operation, then the regulator can be pulled a little more.
  • The engine at maximum speeds and without load begins to “sing”. The impoverished mixture and high turnover causes this failure in the operation of the unit. Setting up all the same screw “h”.
  • Gasoline does not enter the combustion chamber. The breakdown can be caused by clogging of the fuel filter, channels and nozzles of carburetor. To eliminate the malfunction, a complete disassembly of this module of the chainsaw and purge its channels with compressed air are needed (a compressor will be required). To clean the fuel channels qualitatively, you can use a special carburetor liquid for washing. Also, the absence of fuel intake into the engine cylinder may be due to improper adjustment. How it is done with your own hands, it was considered above.
  • Pour the carburetor. In 90% of cases, fuel overflow is caused by a dried and ripe membrane, which presses on a rocker associated with a needle. To change it, you need to remove and disassemble the carburetor.

In general, timely adjustment, as well as on time, the repair of the carburetor of the chainsaws can significantly extend the time of operation of the entire piston system of the engine. Therefore, the configuration of this component of the fuel system should be taken with greater attention.

Why stalls idle

The first and most common cause of this malfunction is the wrong carburetor adjustment. You can adjust the idle speed yourself, for this you need to have a STIHL adjustment screwdriver, which comes with the unit.

The adjusting hole is located on the right side of the STIHL 180 saw on the handle and is indicated by the symbols “-” and “”.

If the Stihl chainsaw does not hold turns and stalls at idle, you can almost 90% be sure that it has violations in the system of the fuel pump, as a rule, it is an air leak into the crankcase through the lining of the pallet, or, much more often, through the seals crankshaft.

The air leaks reduces or even completely stops the impulse, which is supplied through special channels to the fuel pump of the chainsaw. As a result of this, the Stihl 180 chainsaw does not receive the required amount of fuel and stalls at idle.

Diagnose, you can use a special device called a vacuummeter.

The second way to check the operability of the oil seals is to pour gasoline into the engine crankcase and look at them if the oil seals are gasoline, then they cannot provide normal pressure in the crankcase, which will make the work on idle it is impossible.

Chainsaw carburetor repairing Part.1

When working at high speeds, with non.metrmal oil seals, there is a possibility of jamming of crankshaft bearings.

The algorithm for checking the crankcase and seals STIHL 180 for tightness is as follows:

  • The upper cover is removed.
  • Air filter housing and carburetor are dismantled.
  • The handle of the chainsaw is removed.
  • Spin and removes the starter.
  • The side cover and leading star are removed from the opposite side of the side.
  • A piston lock is installed in the candle hole or a lace from an old starter with nodules imposed on it is filled into the cylinder.
  • The flywheel and adhesion of the gasoline saw are unscrewed, after which the parts are removed. It is worth knowing that the clutch of the chainsaw has the left thread and is unscrewed clockwise.
  • The gear of the oil pump drive STIHL 180 is removed.
chainsaw, principle, functioning, carburetor

Having dismantled the chainsaw of the Stihl MS 180, you can see the oil seals, after which you need to fill the crankcase with gasoline and control the leakage. Fill the crankcase, you can through the fuel window in the cylinder, for this the piston must be raised as up as possible.

If leaks are detected, it is necessary to replace defective oil seals, or re.seal the pallet. It is necessary to collect the tool, observing the reverse sequence of the algorithm.

Why stalls at full speed

Very often you can hear the question of why the chainsaws are stalling at full speed. There may be several reasons. Firstly, you need to consider how exactly it died out saw.

Suppose the tool worked normally and suddenly, without visible reasons, it stalled sharply and at the same time the starter does not turn. In such a situation, you can be 100% sure that the chainsaws are jammed and you need to start its overhaul.

The second situation is when the chainsaw of the Stihl 180 worked normally, then gradually lost power in a short time and stalled, while overheating of the cylinder is observed.

In this case, most likely the reason is the air suction under the rubber pipe connecting the carburetor with the cylinder or its gap. The mixture was impoverished, resulting in overheating. Eliminate the cause by changing the pipe.

Glave of a chainsaw at high speeds. a simple carburetor repair

The tool carburetor is exactly the mechanism that most owners are afraid to disassemble on their own. The reason is that this mechanism consists of many small details, the location of which must be remembered during the dismantling work. However, not everything is as scary and difficult as it might seem. To understand how the carburetor has to do with the problem of stopping the engine operation with increasing speed, you need to find out its principle of operation described on the site.

Gazes a chainsaw when pressed due to a carburetor if:

  • The membrane is damaged
  • Clogging of the filter element (mesh in the carburetor). The owners of tools who do not have a fuel filter may encounter this malfunction or it is simply disconnected from the fuel hose
  • Sticking the needle, which can be associated using an outdated fuel mixture
  • Clogging of the channels of nozzles or a carburetor is clogged
  • Bending the connecting part uniting a membrane with a needle for supplying fuel to the fuel chamber of a carburetor. This part is also called a paw, since under the influence of the membrane on it, the needle moves and the opening of the channel. This paw during operation can be bent (developed) or break (when turning off the engine will not start). If the paw is bent, then it can be straightened, but this does not guarantee that the problem is soon repeated soon, so it is recommended to replace the part

It is recommended to clean and wash the chainsaw carburetor, as well as replace faulty parts and elements. After that, it can be set back, not forgetting to replace (if worn out) a sealing gasket between the carburetor and the adapter.

Summing up.

Certainly, every thing we bought has its own expiration date and sooner or later it breaks and how it becomes insulting when the degree of its breakdown is so great that it is not subject to repair. But you must admit that quite often we simply negligently relate to the technique (see. about the correct operation and how to cut down the tree to fall in the right direction). And when she stops working, then we are trying to find the possibilities of eliminating breakdowns, while contacting a huge number of services.

But remember that although the technique breaks, but we can extend its “life”. All that is necessary is to simply take care of her, do a run after replacing the parts (how to run the chainsaws read here) and keep its spare parts clean and order. And then, of course, it will last for many years. The use of exclusively high.quality spare parts and “additives” is also important (see. nozzles for chainsaws). Then your technique will work uninterruptedly, and you will simply forget what repair is.