The Chainsaw Stalls At Idle The Reason


One of the circumstances, due to which the chainsaw does not develop speed when you press the gas, but on the contrary to stall, is a carburetor malfunction. Let’s say the Stihl 180 saw worked properly, and at the end it was put on for a long time and did not even use it. After it was started, while at idle it works perfectly, and when you press the gas, it can stall. Why stalls? The reason is a sticky carburetor injector valve. This is not 100%, but the possibility of such a malfunction is the highest. We advise you to read an article about the device and repair of the Stihl 180 carburetor.

To check the injector, you need to remove the carburetor and disassemble it. To remove, you need to unscrew the two nuts securing the air filter and carburetor, then remove the air filter and the engine control lever, while disconnecting the choke control rod from the carburetor. Next, you need to pull the carburetor a little towards yourself and disconnect the fuel supply hose.


One of the reasons why the chainsaw does not develop speed when you press the gas, but rather stall, is a carburetor malfunction. Let’s say the Stihl 180 saw worked properly, and then it was put on for a long time and did not use it. After it was started, and at idle it works well, and when you press the gas it can stall. Why stalls? The reason is a sticky carburetor injector valve. Of course, this is not 100%, but the probability of such a malfunction is high. We recommend reading an article about the device and repair of the Stihl 180 carburetor.

In order to check the injector, it is necessary to remove the carburetor and disassemble it. To remove, it is necessary to unscrew the two nuts securing the air filter and the carburetor, and then remove the air filter and the engine control lever, while disconnecting the choke control rod from the carburetor. Next, you need to pull the carburetor slightly towards you, and disconnect the fuel supply hose.

It is necessary to remove the fuel hose as carefully as possible, and prepare a plug for it in advance, because fuel should go from it.

Having removed the carburetor, it must be blown out and cleaned of dirt, only after that the carburetor can be unscrewed.

It is necessary to unscrew the cover of the main chamber of the carburetor, this is the one on which the compensator is installed on top. Further, using a bolt of 8 mm and a length of at least 50 mm. Knock out the valve.

It is necessary to knock out the valve by installing the carburetor on a wooden stand, this will ensure its protection from damage to the body.

After the nozzle is removed, you can blow it out with a compressor. The valve should only let air through in one direction, if you can freely blow the valve in both directions, then it is defective and must be replaced with a new one. Collect the chainsaw after the valve is repaired, it is necessary to follow the reverse sequence of disassembly.

To see clearly how the carburetor is being repaired, or rather, how to properly knock out the injector valve from the carburetor body, you can look.

Another common reason a saw can stall when revving up is air leaks into the carburetor. It is possible to check this only with a special tool, but it is worth noting that if maintenance work on the carburetor has not been carried out for a long time, then a new set of gaskets can be installed in the carburetor. In some cases, this helps to solve the problem with its depressurization.

When disassembling the carburetor to replace the gaskets, you need to carefully inspect its needle valve, press the rocker arm and check its lifting. Sometimes, especially after the Stihl chainsaw has stood for a long time with fuel in the carburetor, the needle may burn to the carburetor body and not perform its functions. Simply put, the needle valve will not allow the fuel mixture to pass through. In this case, the saw will not work.

Why the chainsaw stalls, the main reasons. Why the chainsaw doesn’t pick up speed and stalls

If the saw cannot gain speed or stalls when you press the gas, then most likely this is caused not by the tightness of the carburetor or motor crankcase. This problem is eliminated by checking for leaks and adjusting the carburetor.

In addition, this malfunction may be associated with a defect in the fuel tank breather. Due to the formation of a vacuum in the fuel tank during the operation of the chain saw, the required volume of the fuel mixture does not enter the engine, as a result of which it cannot gain speed or stalls. If you stop the chain saw, open and close the fuel tank and turn it back on, it will work normally for about five minutes, and then it will stop picking up speed again or stall.

Another possible reason that the chain saw is not able to pick up speed may be excess carbon deposits in the muffler, which makes it difficult for exhaust gases to escape, which reduces the power and engine speed.

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Why stalls at full speed

Often we hear the question why the chainsaw stalls at full speed. There may be several circumstances. Everything, it is necessary to take into account how exactly the saw stalled. Suppose the tool worked normally and suddenly, without any visible circumstances, it suddenly stalled and at the same time the starter did not turn. Under these circumstances, there is an option to be 100% sure that the chainsaw is jammed and you need to start serious repairs.

The second situation is when the Stihl 180 chainsaw worked normally, then evenly lost power in a short time and stalled, while overheating of the cylinder was observed. Then, most likely, the reason is air leakage under the rubber pipe connecting the carburetor to the cylinder or its rupture. The mixture was depleted, and as a result, overheating appeared. There is an option to remove the cause by changing the pipe.

Repair STIHL MS 180 / disassembly and assembly of the carburetor / stalls at idle

Idle repair of the STIHL MS 1800 chainsaw. The correct method for solving the problem if the chainsaw stalls and.

Filter check and repair

The engine may run intermittently or stall if there is insufficient fuel or air. Causes. clogged air or fuel filter. To check the fuel filter, it is necessary to remove the fuel line hose from the carburetor fitting and direct it into a container. Then press several times to pump fuel. If the fuel is pumped normally, in clearly defined doses, without dirt, then the fuel filter is working properly. If the jet is weak or the fuel is not pumped at all, the filter must be replaced or, if possible, cleaned.

Clogging of the fuel filter with sawdust is one of the reasons for the breakdown of the chainsaw.

The device must be removed from the fuel tank (after draining all fuel from it). On most models, the fuel filter can be hooked out of the wire through the neck. If the filter design is collapsible and can be cleaned, it must be disassembled and washed in accordance with the manufacturer’s recommendations. Otherwise, change to a new filter.

Similar problems can arise when the air filter is clogged with dust, sawdust, or dirt. With an insufficient amount of air, the fuel mixture will be enriched, the fuel combustion process becomes difficult.

To check, remove the filter. During operation, precautions must be taken to prevent dust from entering the carburetor. The device must be cleaned and rinsed in warm water with the addition of detergent. After drying, if possible, blow out with compressed air of low pressure, install in place. If the chainsaw works fine, then the reason has been eliminated, if not, you need to look further.

With constant use of the tool, it is recommended to replace the filters of the fuel and air systems after 3 months.

Checking and repairing the carburetor

The principle of operation of the chainsaw carburetor.

If checking the ignition system, fuel filters, muffler did not give tangible results, the tool still does not want to work normally at minimum speed, you need to check the carburetor.

To adjust the operating modes, there are three screws on the device case, designed to set the minimum rotation speed, maximum speed and idle speed.

On many models, manufacturers install only an idle adjustment screw to avoid incompetent attempts to adjust the device. In all variants of the device, the adjustment must be performed exactly according to the recommendations of the manufacturers.

If the adjustment of the device did not lead to the restoration of the normal operation of the tool, it is necessary to completely disassemble the device with an inspection. It should be understood that a carburetor is a rather complex device, in the absence of experience it is advisable to contact a specialist.

When disassembling, it is important to carefully inspect and flush all jets, air and fuel channels, and filter mesh. Damaged elements must be replaced with new ones. The jets must be cleaned with a soft wire of the appropriate diameter.

It is advisable to carry out the work in appropriate conditions. The carburetor contains many small parts, the loss of any of them will make the device inoperative.

Muffler inspection and repair

Clogged mufflers should be left to soak in warm water and detergent, then thoroughly wipe and dry.

A defective muffler will result in a drop in tool power during operation and stops at idle. Despite the seeming simplicity of this detail, it is also important to follow it. Quite often the muffler is clogged. During operation, wood dust, sawdust, resin particles may get on the grate. High temperatures cause them to stick and build up, and exhaust fumes also form deposits on the surfaces of the spark arrester and other parts. The layer that builds up over time reduces the throughput of the muffler and interferes with the normal removal of exhaust gases. The engine, figuratively speaking, suffocates.

Repair of this unit is not difficult, it is quite within the power of many tool owners. Remove the device from the engine and cover the openings with rags or other material. If the formed layer is too hard, all parts can be left to soak in warm water and detergent. After the plaque has softened, the parts should be washed with a rag or soft brush and wiped thoroughly. Inaccessible areas can be blown out with compressed air or dried with a hairdryer. The use of mechanical means of removal is undesirable.

For the normal functioning of the muffler over a long period of operation, use the lubricants recommended by the manufacturer, observing their shelf life. The mixture must be prepared immediately before work and consumed completely.

Checking the spark plug and ignition system

The manufacturers recommend that the spark plug be replaced annually, regardless of how hard the tool is used. Failure to comply with these tips leads to a completely natural result: failures at idle speed, subsequent failure.

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Typical defects in the ignition system are as follows:

Chainsaw plug malfunctions.

  • The candle was flooded with fuel at the time of start-up. It is necessary to remove it from the nest, dry it, if possible, blow it out with compressed air. Drain the remaining fuel from the cylinder through the mounting hole, blow it out with compressed air. Then install the candle, connect the high-voltage wire, start.
  • No spark on the spark plug electrodes. You need to disconnect the high voltage wire and check for a spark on it. If the spark is normal, check the connection, eliminate any defects. The absence of a spark on the high-voltage wire indicates a malfunction of the ignition unit. This device cannot be repaired, it must be replaced with a new one.
  • The gap between the spark plug electrodes is broken. This parameter for various types of devices can be in the range from 0.2 to 0.5 mm. Checking and adjusting must be carried out using a special feeler gauge or vernier caliper. The required value can be found in the instruction manual of the tool.
  • By the appearance of the candle, you can determine the direction of the search. If the spark plug turns out to be dry after several attempts to start the engine, it means that no gasoline is entering the cylinder. It is necessary to check the fuel supply system and carburetor.
  • The presence of black soot or carbon deposits on the electrodes indicates improper carburetor adjustment or a clogged air filter. Possibly low-quality fuel with large m of oil is used. During normal operation of the ignition system, the electrodes have a uniform gray color and brown deposits on the insulators.

What to do if the chainsaw stalls at idle

The chainsaw stalls at idle speed: many owners of this tool face such a problem. By its structure, the saw was a rather simple tool. But there are times when it fails. The main problem in troubleshooting is determining the correct cause of the abnormal operation. Once the cause has been identified, fixing the defect is usually quite simple.

Chainsaw device diagram.

Possible reasons for failure

The power unit of all chainsaws is a single-cylinder internal combustion engine. Devices of this type are characterized by such malfunctions as a violation inside the cylinder compression, a change in the ratio of the fuel mixture, incorrect operation of the ignition, and poor-quality fuels and lubricants. The main problems in the operation of the power unit are as follows:

  • The engine runs stably at minimum speed, but stalls with increasing speed;
  • Start-up occurs normally, and idle speed is unstable, stalls quickly;
  • Doesn’t start.

Chainsaw electronic ignition circuit.

Abnormal idling can be caused by various reasons. They can be divided into several positions:

  • The throughput of filters (gasoline and air) has been reduced;
  • Abnormal operation of the ignition system:
  • The carburetor settings have spontaneously changed;
  • Malfunction of fuel line elements;
  • Clogged exhaust ducts, muffler;
  • Defects of the piston, cylinder, valves.
The Chainsaw Stalls At Idle The Reason

Repair should begin with an external inspection and checking the presence of fuel in the tank.

What to do if a chainsaw stalls?

Builders, installers, rescuers and summer residents. all of them sooner or later, completing their tasks, take up the chainsaw. And the final result of their activity largely depends on how reliably this tool will work.

The chainsaw is used to cut wood.

It is worth noting that the chainsaw belongs to relatively simple devices. Nevertheless, it, like other mechanisms, 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 installed, it will not be so difficult to return the apparatus to a working position.

Therefore, the first step is to find out what kind of malfunctions there are with a chainsaw and what leads to engine stops at idle.

The car stalls at idle: possible causes

It follows from this that various problems with the main components of any ICE lead to malfunctions: fuels and lubricants, the ignition system, the quality of the air-fuel mixture and compression inside the cylinder.

The main engine faults include the following:

  • The motor will not start;
  • It starts up, but, working unstable, quickly stalls at idle;
  • The chainsaw works fine at idle speed, but stalls under load.

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

Chainsaw internal combustion engine.

Possible clogging of the fuel and air filter;

  • Defective or malfunctioning spark plug;
  • Violation in the initial settings of the carburetor, caused by strong vibrations during the operation of the mechanism;
  • Gas line defects;
  • Incorrect ratio of ingredients in the "fuel mixture";
  • Muffler contamination;
  • Faults of the cylinder-piston group.
  • Spark Plug Problems and Solutions

    It is generally recommended to change this key component of the ignition system at least once a year. But often saw owners forget about this rule. And therefore, one should not be surprised that the device, the maintenance of which is carried out fragmentarily, as a result, does not "hold" idle speed well.

    Chainsaw spark plugs need to be changed once a year.

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

    • Filling the spark plug with gasoline at the time of start. To eliminate the problem, turn the candle out and dry it without igniting it. Excess gasoline is drained from the engine through the hole-socket into which the candle is screwed. After a break of 30 minutes, the candle is put in place, the mechanism starts.
    • No spark due to poor contact of the spark plug tip with the high voltage wire. The connection is checked, in case of violation, the defect is eliminated.
    • There is no spark due to a malfunction of the electronic ignition unit. If there is confidence in the reliability of the connection of the tip with the high-voltage wire, but there is still no spark when the starter is 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.
    • Incorrect spark plug gap. In different types of candles, this indicator ranges from 0.2 to 0.5 mm. The correct clearance is established with a feeler gauge of the appropriate thickness. A larger or smaller gap for a given type of candles is not allowed.
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    Meanwhile, during the initial inspection of the spark plug, it may turn out that the reason why the chainsaw refuses to work is not at all in the defects of the spark plug or other elements of the ignition system.

    Spark plugs may indicate a saw malfunction.

    So, if the candle 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, check the entire gasoline supply chain from the carburetor itself.

    At the same time, the presence of a characteristic black carbon deposit on the plug body is a sign that, probably, the carburetor is poorly adjusted. This causes the fuel mixture to become oversaturated with gasoline. Oil may have spilled into the fuel. In this case, clean the spark plug, replace the fuel and adjust the carburetor.

    Problems associated with improper operation of the fuel system

    The chainsaw periodically stalls at idle speed 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 assemblies, paying attention to possible defects in the surface of the body, mechanical damage, and leaks of working fluids. This also applies to the saw fuel line, which is usually a rubber tube.

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

    Another reason why a chainsaw at idle speed can stall is non-compliance with the ratio of ingredients when preparing the "fuel mixture". The proportions of gasoline and oil included in it must exactly correspond to the proprietary instructions for a particular device. If they are not observed, the engine will not be lubricated sufficiently, and the whole mechanism will stall persistently.

    Idle problems due to faulty muffler

    In case of a noticeable drop in the power of the internal combustion engine at idle mode, after which the car often stalls, you need to remember to check the muffler. The fact is that the specified unit may be heavily clogged with resinous particles and combustion products of the spark extinguisher, falling 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 gas emission. This situation must be corrected without fail. A simple repair of a clogged muffler is carried out as follows.

    Do not clean the muffler with a dry cloth, as carcinogenic carbon particles can enter the respiratory tract.

    The muffler is removed from the engine, 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 cloth soaked in water and detergents. If the muffler is collapsible, wait for all its parts to dry completely. The non-collapsible 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 preventive measure for the normal functioning of the muffler of two-stroke internal combustion engines in the "fuel mixture" of chainsaws, it is recommended to use only high-quality oil and only that which is prescribed by the manufacturer of this unit.

    Substandard carburetor operation

    If it turns out empirically that the filters are clean and the ignition system is not to blame for the fact that the chainsaw is not capable of functioning at idle, the owner of the tool is advised to switch his attention to the carburetor.

    You need to disassemble and assemble the carburetor without haste, since it has many parts without which it cannot work.

    Often the misalignment of this unit, which is responsible for supplying a certain volume of air-fuel mixture to the engine cylinder, leads to unstable operation. 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 can junk. Then it is recommended to clean the fuel and air passages, jets, mesh of the filter element. If the membrane is damaged, it must be replaced with a new and high quality.

    When doing maintenance and repair of a carburetor, you should always remember that it is usually crammed with many very small parts, without which the device simply cannot work normally. Therefore, the carburetor should be disassembled and assembled without haste and with extreme caution.