Why does a chainsaw stall at high speeds? Why does the chainsaw stall? Causes and their elimination

Builders, installers, rescuers and summer residents - all of them, sooner or later, take up a chainsaw when performing their tasks. And the final result of their activities largely depends on how reliably this tool works.

A chainsaw is used to cut wood.

It is worth noting that a chainsaw is a relatively simple device. Nevertheless, like other mechanisms, it periodically fails. When a chainsaw stalls while idling (this is one of the most common malfunctions), the biggest problem is to determine the reasons for this behavior of the device. If the source of the “disease” is correctly identified, returning the device to a working position will not be so difficult.

Therefore, the first thing you need to do is find out what malfunctions the chainsaw has and what leads to the engine stopping at idle.

The car stalls at idle: possible reasons

In order to answer the question of why the saw, periodically capricious, stalls at idle, we must keep in mind that this tool is based on an ordinary two-stroke internal combustion engine.

It follows that malfunctions are caused by various problems with the main components of any internal combustion engine: fuels and lubricants, the ignition system, the quality of the air-fuel mixture and compression inside the cylinder.

The main engine malfunctions include the following:

• the engine does not start;
• it starts, but, working unstably, quickly stalls at idle;
• The chainsaw runs fine at idle, but stalls under load.

The reasons for idle speed problems can be different. But all of them can be reduced to several general positions. So, problems such as:

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Problems with fuel and air filters and their elimination

The chainsaw will stall at idle if the fuel or air filter is clogged. To find out the condition of the first element of the fuel system, you should disconnect the fuel line from the carburetor. If, during pumping, fuel is supplied in doses that correspond to the specified standards, then the cause of the malfunction should be looked for elsewhere. If gasoline flows weakly to the carburetor or does not flow out of the hose at all, then most likely the filter is clogged with debris.

To clean it, it is removed from the tank (all fuel must be drained from the tank before this point). Removal occurs through the filler neck of the tank using a wire hook. The filter is disconnected from the suction hose. If possible, clean the filter. If this is not possible or it is impractical to do this for a number of reasons, the used filter is replaced with a new one.

The chainsaw may stall if the fuel filter becomes clogged.

The air filter can also become clogged with dirt or dust, causing rough idle. It should be remembered that this filter becomes clogged quite often, making it difficult for air to enter the system. The proportion of gasoline in the fuel-air mixture increases, and it becomes excessively enriched. In this case, normal engine operation cannot be expected.

To clean the air filter, remove it with extreme care so as not to shake dust into the carburetor. Next, it is cleaned and washed thoroughly. Detergent is added to the rinsing water. After drying, the air filter returns to its place in the chainsaw.

For normal operation of the cutting tool, it is recommended to change the fuel and air filters every 3 months.

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Spark plug problems and how to solve them

It is generally recommended that this key component of the ignition system be replaced at least once a year. But saw owners often forget about this rule. And therefore, you should not be surprised that a device, the maintenance of which is carried out fragmentarily, ultimately “holds” idle speed poorly.

The spark plug of a chainsaw needs to be changed once a year.

Therefore, you should pay attention to the following malfunctions associated with the operation of this system:

1. Filling the spark plug with gasoline at start-up. To eliminate the problem, turn the candle out and dry it without calcining it. Excess gasoline is drained from the engine through the socket into which the spark plug is screwed. After a break of 30 minutes, the candle is installed in place and the mechanism starts.
2. Lack of spark due to poor contact of the spark plug tip with the high voltage wire. The connection is checked, and if it is broken, the defect is eliminated.
3. There is no spark due to a faulty electronic ignition unit. If you are confident that the connection between the tip and the high-voltage wire is reliable, but there is still no spark when the starter is turned on, then the cause of the breakdown may be a malfunction of the ignition unit. This component is not restored, it is only replaced with a new one.
4. Incorrect gap between spark plug electrodes. In different types of candles this figure ranges from 0.2 to 0.5 mm. The correct gap is set using a feeler gauge of the appropriate thickness. A larger or smaller gap for a given type of spark plug is not allowed.

Meanwhile, during an initial inspection of the spark plug, it may turn out that the reason why the chainsaw refuses to work does not lie in defects in the spark plug or other elements of the ignition system.

Spark plugs can indicate a malfunction of the saw.

So, if the spark plug turns out to be completely dry, this may mean that the original problem lies in the impossibility of fuel entering the combustion chamber. In this case, you should check the entire gasoline supply chain from the carburetor itself.

At the same time, the presence of a characteristic black soot on the spark plug body is a sign that the carburetor is probably poorly adjusted. Because of this, the fuel mixture becomes oversaturated with gasoline. There may be oil in the fuel. In this case, you should clean the spark plug, replace the fuel and adjust the carburetor.

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Substandard carburetor operation

If it turns out experimentally that the filters are clean and the ignition system is not to blame for the fact that the chainsaw is not able to function at idle, the owner of the tool is recommended to switch his attention to the carburetor.

You need to disassemble and reassemble the carburetor without haste, since it contains many parts without which it will not be able to work.

Often, unstable operation is caused by misalignment of this unit, which is responsible for supplying a certain volume of air-fuel mixture to the engine cylinder. It can be adjusted with three special screws located on the carburetor: screws for maximum and minimum speed, as well as a screw that controls idle speed.

Some manufacturers, fearing unwanted interference from incompetent people, supply their products with only one idle screw. But in both cases, carburetor adjustment can be made only by strictly following all the manufacturer’s instructions.

However, even after adjusting the carburetor, in accordance with factory standards, this unit may act up. Then it is recommended to clean the fuel and air channels, jets, and filter element mesh. If the membrane is damaged, it must be replaced with a new one of high quality.

When carrying out maintenance and repair of a carburetor, you should always remember that it is usually stuffed with many very small parts, without which the device simply cannot work properly. Therefore, the carburetor should be disassembled and reassembled without haste and with extreme caution.

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Problems associated with improper operation of the fuel system

The chainsaw periodically stalls at idle also due to a violation of the integrity of the fuel line or an incorrect ratio of the ingredients of the “fuel mixture” consisting of gasoline and oil.

Before each switching on of the cutting mechanism, it is necessary to visually inspect its blocks and components, paying attention to possible defects in the surface of the housing, mechanical damage, and leaks of working fluids. This should also be done for the saw's fuel line, which is usually a rubber tube.

If the device was (especially for a long time) in a damp place and had to withstand sharp fluctuations in air temperatures, this tube could simply crack. This fuel line is not suitable for further use and should be replaced.

Another reason why a chainsaw may stall at idle is failure to comply with the ratio of ingredients when preparing the “fuel mixture”. The proportions of gasoline and oil included in it must exactly correspond to the branded instructions for a particular device. If they are not followed, the engine will not be sufficiently lubricated, and the entire mechanism will persistently stall.

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Idling problems due to a faulty muffler

If there is a noticeable drop in the power of the internal combustion engine at idle, after which the car often stalls, you need to remember to check the muffler. The fact is that this unit may be heavily clogged with resinous particles and combustion products of the spark extinguisher, which fall out on the walls of the muffler in the form of thick deposits.

As a result, the resulting impermeable layer interferes with the normal exhaust of exhaust gases. This situation must definitely be corrected. A simple repair of a clogged muffler is carried out as follows.

Cleaning the muffler with a dry cloth is not allowed, as carcinogenic carbon particles can enter the respiratory tract.

The muffler is removed from the engine and disassembled (if this type of muffler can be disassembled). In this case, it is necessary to plug the remaining holes from under the muffler.

The entire assembly and its individual parts are thoroughly washed with a rag soaked in water and detergents. If the muffler is dismountable, wait until all its parts are completely dry. The non-removable unit is dried using an ordinary household hair dryer. Cleaning this device with a dry cloth is not allowed, otherwise carcinogenic particles that form carbon deposits may enter the human respiratory tract.

As a preventative measure for the normal functioning of the muffler of two-stroke internal combustion engines, it is recommended to use only high-quality oil in the “fuel mixture” of chainsaws and only that which is prescribed by the manufacturer of this unit.

The Stihl 180 chainsaw does not develop speed, or after you release the gas trigger, it continues to work without slowing down. These problems are quite common. Let's try to understand the reasons that result in the occurrence of such malfunctions. Also in this article we will look at how to diagnose if the chainsaw does not pull.

There may be several reasons for the lack of traction and poor speed of the chainsaw. Therefore, you should not immediately start disassembling and repairing the carburetor, since the reason may not be hidden in it.

The Shtil MS 180 chainsaw is equipped with a reliable carburetor, on which the manufacturer has limited the ability to adjust the power and maximum engine speed, so if the chainsaw loses traction, the carburetor is the last place to look for problems.

Muffler

You may ask, which is the first? The answer is a muffler. The muffler is responsible for exhaust gases and extinguishing the flames in them. All combustion products pass through it, which can clog it over time. The situation with a muffler clogged with soot is far from uncommon, and it occurs due to an incorrect fuel mixture.

With a normal ratio of gasoline to oil, combustion products are not so saturated with soot that they clog the muffler. If the amount of oil is more than normal, excessive carbon deposits will form during its combustion. Further, carbon deposits accumulate under the piston rings and in the muffler of the Stihl 180 chainsaw. Thus, a coked muffler is the most harmless thing that can happen, the maximum damage from excessive carbon deposits is the need to replace the piston.

How to check the muffler

To check the muffler, it must be removed from the chainsaw. To do this, using an 8 mm socket, unscrew the two fastening nuts and remove the part.

Important: after the muffler is removed, it is necessary to check the integrity of the gaskets between it and the cylinder, since very often they stick and break when the muffler is removed.

You can clean the part mechanically, using screwdrivers or a knitting needle, and then blow it thoroughly with compressed air. The seat on the muffler can be cleaned with sandpaper to remove burnt parts of the gasket.

The muffler must be installed in the reverse order.

Important: when tightening the muffler mounting nuts, do not over-tighten the nuts, as the threads on the screws can be stripped.

The second reason why a calm chainsaw engine may reduce power and not develop speed is a blockage in the fuel system. As a rule, the first place to start looking for a blockage is the fuel filter.

Checking the fuel filter

The fuel filter is installed in the tank of the Shtil 180 chainsaw, and it is not very convenient to remove it. To make the process easier, you can take a small piece of aluminum wire and bend it at the end, then use it to hook the fuel hose and remove it, along with the filter, from the tank. To check the filter, you need to blow into it; if air does not pass through, then the cause has been found, and the filter needs to be replaced.

If the filter is clean, you need to check the fuel hose for clogging. To check, you need to disconnect it from the carburetor and, with the air filter removed, blow into it. If a blockage is detected, you can clean the hose mechanically, using a wire, and then blow it out with compressed air.

Strainer in carburetor

The last likely place for a blockage to form is the strainer in the carburetor. In the diagram below, it is indicated by the number 13.

In order to clean the mesh filter, you need to remove the carburetor from the Shtil 180 chainsaw. The work begins by removing the top cover of the saw, after which, using an 8 mm socket, unscrewing the two fastening nuts. Next, the filter housing is removed from the guides, after which the air damper rod and the engine control lever are disconnected. Lastly, the fuel hose and throttle linkage are disconnected, after which the carburetor can be removed from the guides.

The carburetor strainer is installed in the fuel pump chamber; in order to get to it, one screw securing the pump cover is unscrewed and it, along with the gaskets, is removed.

The mesh filter can only be cleaned using compressed air. Any mechanical methods are strictly prohibited, since the mesh is very soft and easily changes shape. When you press it, it easily wrinkles and bends form along the edge of the seat, through which unfiltered fuel can enter the carburetor.

During the cleaning process, the seat with the filter installed in it must be half covered with your finger and only then blow with air, otherwise the mesh may fly away and it will no longer be possible to find it.

Carburetor depressurization and nozzle blockage

Sometimes, when the screws securing the carburetor cover are loose or the gaskets have become unusable, the chainsaw may also experience a loss of power. To eliminate the possibility of this malfunction, it is necessary to check the integrity of the gaskets and the tightness of the screws on the carburetor covers. To do this, you need to remove it from the engine (the algorithm is described above) and disassemble it. Defective gaskets must be replaced using spare ones from the repair kit for the Shtil MS 180 carburetor.

In the case where a complete check of the fuel supply and exhaust gas system has been carried out, but there are no results. The main fuel injector valve needs to be checked. To check, you need to knock it out of the carburetor body. All work should proceed according to the following algorithm:

1. The carburetor is removed from the chainsaw.
2. The four screws securing the cover with the compensator are unscrewed, after which the cover can be removed.
3. The carburetor is installed on a wooden lining, after which, using a bolt with a diameter of no more than eight millimeters and a length of 50, it is knocked out into the internal cavity of the carburetor.
4. Next, you need to select a small hose, the inner diameter of which matches or is slightly smaller than the outer diameter of the nozzle and put it on the nozzle.
5. The next step is to blow inside the hose. If it only blows in one direction, the nozzle is working properly; if it blows in both directions or does not blow at all, then the valve needs to be replaced.

All of the above actions should help in eliminating the problem associated with the fact that the chainsaw does not pick up speed, otherwise, a full diagnosis at the manufacturer’s service center will help.

Why does the chainsaw not slow down?

There may be several reasons why a chainsaw does not slow down:

• throttle spring broken;
• jamming of the gas trigger;
• the throttle linkage is bent;
• The corkscrew of the throttle shaft is lost, causing it to jam.

It is not difficult to solve all these problems; you need to conduct a careful inspection and accurately determine the cause, and then replace the faulty part. As a rule, if the chainsaw picks up speed well, idles and has normal power, then the problem with the fact that it does not slow down is purely mechanical. And finding and eliminating a mechanical fault is much easier than identifying and stopping air leaks in the chainsaw crankcase.

Video

Calm 180 does not develop speed, a video of the most common reason can be seen below. In it, the owner of the Shtil ms 180 chainsaw tells his story of solving a problem with loss of power.

Conclusion

If the first signs of loss of power (reduction in speed) appear with the Shtil MS 180 chainsaw, under no circumstances should you continue to work, but you should immediately contact a specialist or carry out diagnostics and fix the malfunction yourself. There are not many reasons for power loss and you can cope with them even without certain skills. The main thing is to calmly analyze the behavior of the saw and find out the reasons why it stopped pulling (the speed dropped), and eliminating the malfunction is not a difficult task.

Malfunctions occur both in expensive German or American modifications of chainsaws, and in their cheap Chinese counterfeits. It’s nice when the power tool starts up smoothly: the saw warms up and gradually reaches the rated power declared by the manufacturer, which is provided throughout the entire operating cycle. Things are worse if everything happens the other way around: after pulling the gas cable, the unit begins to slip, runs jerkily after short pauses, stalls and restarts with the pusher.

There can be many reasons for this phenomenon, as well as scenarios for the development of events. Let us consider in detail each working situation and the breakdowns that preceded them.

What to do if the chainsaw does not idle?

Problems with idle speed are considered constant companions of chainsaws. There may be several prerequisites that could lead to stalling at the time of start-up and cranking of the chain when idling, the main ones being:

• air and gasoline filters are clogged;
• poor quality fuel mixture or improper preparation;
• problems with the ignition module;
• a carburetor whose settings no longer correspond to the load on the saw;
• motor elements are deformed or rusted.

A series of actions are performed sequentially:

• wash the fuel hose or replace it with a new one,
• Clean the air filter, which could be clogged with sawdust and dirt particles. Modern air filters are reusable, they can be washed with the addition of detergent, completely removing them from the saw body;
• check gasoline and motor oil, which may be of poor quality or simply not suitable for working with this saw;
• testing spark plugs and carburetor.

Eliminating one or more possible problems will usually restore the saw to its former strength.

Why doesn't the chainsaw gain momentum?

Starting up is a complex multi-level process in which almost all life support systems of the saw are involved. That is why the fact that the chain saw loses speed, turns on intermittently and feels confident only at idle should be considered from different angles.

The following factors could lead to this:

• a faulty motor - its service life could be exhausted, and the piston rings and cylinder could wear out, become deformed, or even succumb to corrosion;
• a faulty spark plug or the coil itself - as a result, the spark necessary to ignite the air-fuel mixture is not produced;
• unbalance of the carburetor screws, as well as a number of reasons that could cause it to fail.

The chainsaw does not develop speed: we test the device for malfunctions

The ignition module can be diagnosed for problems visually. To do this you need:

• turn out the spark plug;
• evaluate its appearance (it should not be filled with gasoline or contain a black coating);
• check the distance between the coil and magnets (up to 0.2 mm);
• if necessary, examine the spark plug block for spark supply using a working power cable.

If after checking no defects were found, you should proceed to checking the carburetor unit.

This working unit is one of the most vulnerable in modern chainsaws. New tools that go on sale from the factory have basic settings for low and high speeds, which must be reinstalled after running in and running in all the parts. Similar actions are performed if the saw does not develop traction corresponding to the maximum torque according to the instructions.

In this case, you need to reconfigure one of them - the “H” jet, which is responsible for the operation of the saw under load. To do this, it is enough to adjust the fuel supply with the engine running at the highest chain rotation speed, using the tachometer and the operating instructions.

Other chainsaw malfunctions

Many users encounter problems when the chainsaw does not slow down. The device reaches maximum power in a matter of seconds, which cannot be reduced.

This may be due to the fact that:

• the throttle valve does not function - its spring or traction element has weakened;
• the power switch does not switch well;
• The throttle shaft has lost its spin.

But the opposite situation can also happen - when the saw gains power uncontrollably. The reasons why the chainsaw itself gains momentum should be looked for in:

• carburetor - it needs to be cleaned or reconfigured;
• fuel supply system - gas filter, fuel hose;
• malfunctions of the cylinder-piston pipes or pipes connecting them to the carburetor.

There are quite a lot of breakdowns that manifest themselves through speeds that are atypical for a particular part of the operating cycle. But careful attention to the instrument will help to diagnose them in time and return it to normal operation.

A chainsaw is a worthy replacement for hand saws and axes. Today, this tool is available in almost every household - it is indispensable when arranging a personal plot, construction and repair work. Intensive use and improper care of the tool can lead to premature failure. However, it is not at all necessary for the owner of a chainsaw to immediately contact a workshop - many of the malfunctions that can happen to it during operation can be easily eliminated on their own.

Chainsaw design and general classification of faults

The main condition for successful repair is correct. Therefore, in order to determine why the chainsaw failed and, most importantly, how to make it work again, you first need to know the features of its design.

It should be noted that it is not particularly complex, as it includes:

In order to simplify the diagnosis of faults, they are usually divided into two main categories:

• engine malfunction;
• malfunctions of other chainsaw components.

Most often, failures occur in, however, other parts of the tool can fail at any time due to intensive use or improper care. How to determine exactly where the breakdown occurred? Simple logic will help us with this.

If the problem is in the engine, it will:

• won't start;
• stall;
• work unsteadily;
• overheat;
• smoke;
• develop insufficient power.

As for all other faults, as a rule they manifest themselves when the engine is running normally.

Starting the engine: checking the spark plugs

If the chainsaw does not start, the first thing to do is check the tank for . By the way, it must be prepared in the proportions specified by the engine manufacturer, otherwise the tool simply will not start.

After making sure that the fuel mixture is correct and available, you should check the ignition system. To do this, you need to inspect the spark plug.

Her condition can say a lot:

• dry candle

indicates that the fuel mixture does not enter the carburetor, which means the problem is not in the ignition;

• fuel-spattered candle

is the result of an excess of the fuel mixture, which lies either in a violation of the engine starting algorithm or in incorrect carburetor adjustment;

• carbonated candle

This is a signal about the presence of low-quality oil in the engine lubrication system, incorrect carburetor settings, or an incorrectly prepared fuel mixture.

If it is splashed with fuel, it must be thoroughly wiped after removal. The fuel supply system should also be cleaned. To do this, it is closed, after which the starter is turned on. A candle covered with soot must be carefully cleaned using an awl and sandpaper.

When checking spark plugs, you should pay attention to the distance between the electrodes (the normal gap is 0.5-0.65 mm), as well as the condition of the gasket and the presence of a spark. A damaged or worn gasket will need to be replaced, and the spark can be checked by putting on the ignition cable, connecting the cylinder and spark plug nut, and turning the starter.

If the discharge does not occur, the spark plug needs to be replaced. If a spark does not appear even with a new spark plug, then the problem is in the connection to the high-voltage wire or in it itself.

DIY chainsaw repair: fuel supply system

If the fuel mixture does not enter the cylinder, but the spark plug works normally, this may mean that:

1. The fuel filter is clogged.

To clean this unit, remove the fuel hose and check the flow. If it is weak, the filter must be removed through the filler hole of the fuel tank and cleaned or replaced if completely worn out.

1. The breather is clogged.

This is nothing more than a hole in the fuel tank cap, which is cleaned with an awl.

1. The fuel mixture is not supplied or is supplied in insufficient quantities.

There may be several reasons for this:

Troubleshooting muffler problems

If it works fine at low speeds, but starts to stall and smoke at high speeds, the problem may be hidden in the muffler.

To check the quality of its work you should do the following:

Dry cleaning without respiratory protection is not recommended. Carcinogens present in carbon deposits will be released into the surrounding atmosphere in the form of dust, the inhalation of which is extremely dangerous to health.

To prevent clogging of the muffler during operation of the chainsaw, you should carefully monitor the composition of the fuel mixture and the quality of its components.

Repair of cylinder-piston group (CPG)

If the chainsaw engine does not start or cannot develop normal power, it is likely that there is not enough pressure in the engine cylinder to burn the fuel mixture. The reason for this may be wear and tear of elements - piston, rings, bearings, etc. In order to assess the condition of this unit, it should be visually inspected after first removing the muffler.

For a more complete diagnosis, a compression gauge is placed in the spark plug hole of a two-stroke chainsaw engine. It is used to measure compression in the engine. Based on the test results, one can judge the condition of the CPG, but accurate facts can only be obtained by completely disassembling the unit.

If the piston is chipped or scratched, it will obviously have to be replaced. The same applies to deformed or broken piston rings - for normal engine operation they must be fully functional and free of carbon deposits.

Checking the carburetor and signs that it needs adjustment

Correct operation guarantees maximum efficiency of the chainsaw, that is, it is possible to develop full power with the most economical consumption of the fuel mixture. Adjustment of this unit is usually carried out by the manufacturer, but its design provides for the possibility of adjustment during operation.

The fact that such adjustment will have to be made by the owner of the chainsaw is evidenced by:

1. Strong vibrations or damage to the protective cap.
2. CPG wear.
3. Carburetor clogged.
4. Inability to start the engine or its spontaneous stopping after starting.
5. Increased fuel consumption and exhaust emissions with a simultaneous decrease in engine power.

The chainsaw carburetor is adjusted in strict accordance with the manufacturer’s instructions using three special screws, which are responsible for the maximum (“M”) and minimum (“L”) speeds, as well as engine idle speed (“T”). In order to exclude unwanted interference by an inexperienced user in the operation of the carburetor, some manufacturers install only one idle screw.

Calibration algorithm and safety precautions when troubleshooting a chainsaw carburetor

Carburetor adjustment is performed in two stages:

1. Basic (carried out with the engine off).
2. Finish (carried out with the engine running, preheated).

For basic adjustment, screw screws H and L until they stop and turn them back 1.5 turns. Final adjustment requires that the engine be warmed up for 5-10 minutes at low speeds.

The finishing is performed by turning out the idle screw until the minimum engine speed is reached (its operation must be stable and the chain must be motionless). If the engine stops idling, the screw must be returned back, and if the saw chain still moves, you should continue turning it counterclockwise.

Calibration check is performed by test:

1. Acceleration (when you gently press the accelerator, the engine should quickly gain speed to its maximum).
2. Maximum speed (if there are misfires, screw H should be loosened slightly).
3. Idling (the chain should not move, and the engine should pick up speed as quickly as possible).

If the owner of the chainsaw is not familiar with the carburetor structure and does not have the necessary tools to calibrate it, you should contact a specialist. A carburetor is a very complex unit, so any incorrect action can lead to irreversible consequences, such as complete engine failure.

Other chainsaw malfunctions

If the diagnostics showed that everything is in order with the engine and its systems, then the cause of the malfunction should be sought elsewhere. The most common problems are:

If the cause of tool failure is not visible to the naked eye, as is the case with the engine, it is necessary to carefully diagnose the faults and eliminate them in accordance with the manufacturer’s recommendations and safety regulations.

DIY chainsaw repair, video

Prices for chainsaws are falling and this makes them more popular and affordable not only for professionals, but also for ordinary, so to speak, amateurs. However, a common dependence - the lower the price, the less reliable the device and the more often malfunctions appear, is also relevant for chainsaws. But for a chainsaw of any price range, most malfunctions can be avoided with proper operation, care and timely maintenance of the equipment. But no one is immune from the breakdown of a chainsaw, as well as any other equipment. It is therefore proposed to consider main types of chainsaw malfunctions, methods for diagnosing, eliminating and repairing them.

All the main malfunctions of chainsaws can be divided into two main categories:
- malfunctions of the engine and its various components: fuel preparation and supply system, ignition, piston group with crankshaft, exhaust gas exhaust system;
- malfunctions and breakdowns of other components: lubrication system, clutch, chain brake, tire and others.

Chainsaw engine malfunctions

Here are various malfunctions in the operation of a chainsaw engine that occur most often. These main malfunctions boil down to the following symptoms:

the engine does not start (quite general and the reasons can be quite different);

works unsteadily;

starts, but often stalls;

overheats quickly;

does not develop power, i.e. It runs fine at idle, but stalls or "chokes" under load.

It smokes a lot and the power drops.

Problems starting the engine

It is very important to correctly determine the cause of the malfunction, because otherwise we simply cannot eliminate it. If, when trying to start the chainsaw, there are no extraneous sounds (knocking, grinding, etc.), then very often it turns out that in fact there is no breakdown. For example, if you start the chainsaw incorrectly and pull the choke for a long time, the engine simply floods and it is very difficult to start it.

In order to properly start a cold chainsaw engine, set the lever or switch to the “throttle closed” position. Then you need to pump the mixture into the carburetor, if there is a fuel priming pump. Pull out the starting handle until the engine resistance becomes noticeable, and vigorously pull in amplitude, moving your hand to the side. After two or three such movements, the engine should first start and then stall. If this does not happen, then you need to move the lever to the half-throttle position or simply to the working position and then continue to start the chainsaw in this mode. For many chainsaws, the “half throttle” is automatically locked when the air damper is pulled out. Some models have a key ignition switch; it is important to make sure it is turned on.

If the engine does not start, then the first thing to do is unscrew and inspect the spark plug. There are cases when at a plant in the cold season, the combustion chamber is filled with fuel. Then you also need to unscrew the spark plug, dry the combustion chamber by idling, clean the spark plug, screw it in and repeat the start. It is advisable to immediately check for the presence of a spark - put a cap with a high-voltage wire on the unscrewed spark plug, place it on the cylinder and pull the starter. Visually we observe a frequent blue spark - good. Screw the spark plug into place and start it. If there is no spark, change the spark plug and try again. No again - we check the connection of the high-voltage wire to the spark plug, the coil and the ignition system.

In general, the type of malfunction can be judged by the condition of the spark plug.

• Dry. Most likely, the fuel mixture is not getting into the cylinder. The problem is not in the ignition system, so screw the spark plug back in and check the fuel supply system.
• Wet, heavily splashed with fuel. The reason for the excess fuel mixture lies either in a violation of the starting rules, as described above, or in incorrect carburetor adjustment.
• Covered with black soot. This may indicate the use of low-quality oil, an incorrectly adjusted carburetor, or an incorrectly calculated ratio of gasoline to oil. The spark plug should be washed, removed from carbon deposits with a sharp object (an awl or a needle), the electrodes should be wiped with sandpaper and placed in place.

When checking the spark plug, you need to pay attention to the gap between the electrodes: 0.5 to 0.65 mm is considered normal. A damaged or worn gasket must be replaced.

Checking and adjusting the chainsaw carburetor

A properly adjusted chainsaw carburetor ensures that it operates efficiently at full power with the most economical fuel consumption.

The need to adjust the carburetor of a chainsaw rarely arises, since the adjustment is initially carried out by the manufacturer to achieve optimal operating mode. The adjusting screws are designed for more precise adjustment of the chainsaw carburetor if necessary.

When and why does this need arise?

Among the reasons for the failure of fixation of the adjusting screws, the most common are the following:

• Severe vibration or damage to the protective cap. This happens rarely, but it does happen.
• Serious engine wear (piston). Of course, in this case it is worth taking more care of repairing the chainsaw engine, but still adjusting the carburetor can improve its functionality for a while.
• Blockage in the carburetor due to damage to the air filter, poor quality gasoline or due to the formation of scale. In this case, in addition to adjusting the carburetor, flushing it cannot be avoided.

What signs indicate the need to adjust a chainsaw carburetor?

• Firstly, the engine does not start, or it starts, but immediately stalls. This most often occurs due to a lean fuel mixture.
• Secondly, a significant increase in fuel consumption and exhaust emissions. An increase in exhaust emissions indicates that the fuel does not burn completely, which means that the cause may be oversaturation of the fuel mixture.

The scheme for adjusting the carburetor of a chainsaw may differ slightly depending on the manufacturer (the process of adjusting the carburetor of a chainsaw of a specific brand and model is described in detail in the operating instructions), but the general principles remain the same for all brands. The purpose of adjusting the saw is to change the quantity and quality (richness) of the fuel mixture supplied to the engine cylinder.

To learn how to adjust the carburetor on a chainsaw, you should learn to distinguish between three screws (some models have only one).

Screws L and H are similar only in appearance, in fact they are different

Each screw has its own letter designation:

• “L” is used to adjust low speed;
• “H” is necessary to adjust the upper speed;
• “T” is needed to adjust the idle speed (models with one screw only have it).

There are mandatory safety requirements that must be observed when adjusting the carburetor of any chainsaw:

• Make sure the chain is facing away from you.
• The saw must be firmly positioned on a level surface, and its cutting part must not touch any objects.

Please note: you will find the exact values ​​of the angle of rotation of the adjusting screws in the operating instructions for your specific chainsaw model. Carefully following the manufacturer's instructions will help you avoid engine damage.

The process of setting up a chainsaw carburetor consists of two stages: basic (engine off) and final (warm engine running).

Basic adjustment of a chainsaw carburetor

Slowly turn the maximum and minimum speed adjustment screws (H and L) clockwise until they stop, then turn them counterclockwise 1.5 turns.

Final adjustment of the chainsaw carburetor

Idle speed adjustment

Before this adjustment step, it is necessary to warm up the engine for 5-10 minutes, avoiding high speeds.

By turning the idle speed adjustment screw (T/LA/S) counterclockwise, achieve the minimum speed at which stable engine operation will be ensured. Make sure the chain does not move. That is, if the engine stops at idle, turn the idle speed adjustment screw clockwise. If the chain is driven, turn the screw counterclockwise.

To complete the adjustment of the chainsaw carburetor, you need to check the engine for acceleration and maximum speed.

Acceleration check

To check the engine for acceleration, gently press the accelerator and make sure that the engine quickly picks up speed from idle to maximum speed (from 2800 to 11500-15000 revolutions - depending on the brand and model of the saw). If the engine picks up speed slowly, slowly turn screw L counterclockwise (no more than 1/8 turn).

Adjusting the maximum speed

The maximum speed is adjusted using screw H. The speed increases when it is turned clockwise, and decreases when it is turned counterclockwise.

The highest rotation speed of chainsaw engines varies from 11,500 to 15,000 rpm. Higher speed can be dangerous for the engine and is simply not provided by the ignition. Therefore, the maximum speed can be determined by the occurrence of ignition interruptions. If they appear, turn screw H slightly counterclockwise.

Re-check at idle

After you have adjusted the acceleration and maximum engine speed, be sure to re-check the operation of the chainsaw at idle. When the carburetor is correctly adjusted, the following conditions must be met:

1. at idle, the chain should not move;
2. the engine should pick up speed quickly;
3. The engine should operate like a four-stroke engine.

If the operation of the chainsaw does not meet at least one of these conditions, the adjustment procedure (except for the basic stage) will have to be repeated again.

Muffler.

You also need to check the muffler. If it is collapsible, then we disassemble it and inspect it, removing all the carbon deposits. In some chainsaw models, the muffler will have to be twisted; there is no other way to check it. The non-removable muffler is dried with a hairdryer after washing. Remember that carbon deposits contain substances that are carcinogens, and dry cleaning, which could result in their inhalation, is unacceptable. When removing the muffler, plug the engine exhaust hole with a clean rag. Do not underestimate this breakdown - the muffler will clog, the chainsaw will lose power or will not start at all. One of the reasons why the muffler may become clogged is the use of a fuel mixture with an excessive amount of oil (the amount of oil is more than the manufacturer recommends), and the use of either oil not intended for two-stroke engines or low-quality oil.

Chain lubrication system

It’s rare that a chainsaw repair manual goes without mentioning malfunctions of the chain lubrication system, which are quite common. They usually manifest themselves in the lack of or insufficient supply of lubricant to the chain and in oil leaks. If the chain turns out to be dry, first of all you need to inspect and clean the channels through which oil is supplied to the bar. Their clogging is a common occurrence.

If there is a significant (small is considered normal) oil leakage, you need to check the tightness of connecting the tubes to the pump fittings. They may fall off or crack. Violation of the tightness of the oil line, in addition to drips, can also lead to insufficient lubrication of the chain. The pump begins to suck in air, which affects its performance. Violation of the tightness is eliminated by replacing the tubes or sealing them with sealant.

Oil pumps come in different designs and can also be driven in different ways. Very often there is no need to change the entire oil pump, it is enough to change its moving part called the plunger; often it is this that fails due to the ingress of a large amount of dirt and sawdust; it simply jams and its edges are licked off. The oil pump is usually driven by a drive sprocket or a special gear on the crankshaft.

The most serious failure of the lubrication system is cracks in the oil pump housing. In this case, it will have to be replaced.

Chain brake

Failure of the chain brake to operate may occur due to contamination of the underframe space and the brake band with sawdust or grease. This also leads to tape wear. In the first case, you need to clean the under-axle space, in the second, replace the brake band.

If you have a brushcutter on your farm - use, maintenance and repair - this will help you. Moreover, you can make your own lawn mower from a chainsaw, thus unifying the tool.

Chainsaw maintenance

Before each start of the chainsaw make sure the chain is in good condition, its teeth are sharp and its tension is normal - without sagging, but not too tight, so that it can be pulled slightly away from the blade.

Sharpening of the chain is carried out both using a special machine and manually using a file and a template for a specific chain tooth pitch. In any case, the instructions for your product contain all the necessary information on sharpening the chain.

After each use of the saw, it must be cleaned. The chain, saw blade are cleaned (sawdust is removed from the chain groove), and the air filter. The saw body and engine air cooling fins, as well as other cracks and grooves, should also be freed from inevitable sawdust. After using the saw, you should turn the blade over so that it wears evenly, and also lubricate the blade sprocket located in the front part (if there are grooves for lubrication).

After a week of regular use you should:

• check the spark plug for the correct gap, make sure there is no deposits on the working elements of the spark plug;
• inspect the saw blade for the appearance of burrs in the places where the chain passes and, if any, remove them with a file. It is also necessary to check whether the geometry of the saw blade is broken - in case of bending and other damage, the blade must be replaced;
• Check the functionality of the start key and other controls.

Before long-term storage of the chainsaw, you must empty the fuel tank and oil container! And yet, the chain and bar must be stored separately, since together they rust, apparently forming an electrochemical couple.