STIHL chain saw cuts out when throttle


Chainsaw has long been a luxury, and not a necessary tool for those who have a summer cottage or home ownership. However, as well as no matter what other equipment, this tool tends to fail, in spite of the uncomplicated device.

Systemizing the main faults means:

  • complete absence of motor winding
  • the engine starts and stops
  • the tool does not run smoothly
  • Stoppage of operation under load
  • loss of power.

If your chainsaw won’t start at all, the reason you’ll like more in the following:

  • Manufacturing defect
  • Lack of fuel
  • Trouble with starting the ignition system
  • Lack of spark from spark plugs
  • Bad fuel mixture
  • Clogged carburetor
  • Trouble with the high-voltage wire
  • Lack of compression.

What to do if your chain saw fails to start and stops?? You need to look carefully at the prerequisites for this purpose.

STIHL chain saw fails to start and stops: why, how?

The reason that the chainsaw can stall immediately after starting is due to problems with a certain part of the equipment.

Why chain saw fails to start and stops

If the equipment starts poorly “cold” the problem may be a lack of compression, t.е. the rings are worn out because of long use, they need to be replaced. Sometimes a problem with the muffler or poor contact between the spark plug and the wire is the reason why the engine doesn’t start well when not warmed up.

Chainsaw “bog” what to look for and how to fix

READ STIHL chain saw does not rev

Another cause of poor starting performance is a worn or damaged gasket or rubber seals in the carburettor booster pump, causing additional air flow that results in high RPM.

Resolving malfunctions

Proper use of the equipment, with periodic inspection of the components to prevent damage. To correct malfunctions, all components must be checked to ensure that they are functioning properly.

If the chainsaw starts and stops, the cause can be corrected by your own efforts. If it is a shortage or improperly mixed fuel, you need to fix it. As a preventive measure, always drain away any fuel left when the chain saw is not in use.

Spark plugs should be checked periodically. This should include removing fouling that clogs the connection gap, as well as checking the tips for fuel. Another cause of trouble with spark plugs may be that they are wet with gasoline. To do this, they should be removed, wiped with a cloth and left to dry. Replace defective spark plugs.

STIHL chain saw starts and stops reason.

If there is no spark between the spark plug and the high-voltage wire, but if they are well connected, the ignition unit must be replaced.

READ STIHL chain saw does not rev up under load

A clogged muffler is a very common cause chainsaw

Starts and then immediately shuts down. To fix the problem, you need to dismantle the muffler, clean it from soot with sandpaper or a special chemical solution. If the chainsaw model is non-disassembled, chemicals are poured into the system and stay there for several hours, then it blows.

The carburetor needs to be adjusted if the chain saw

idle stalls. Fine tuning is difficult, so it usually needs to be done in a service shop. But, on some models there are elements for its adjustment, it is enough to turn the bolt by half a turn to increase the rotation of the chainsaw, the problem will be solved. If the jets, nozzles, filters and passages are clogged, the carburettor must be disassembled and cleaned. If the seals, gaskets or oil seals are worn, replace them and check for trapped air.

If there is a problem with the fuel or air filter, replace the fuel pump or clean the air filter.

If the breather plug is clogged, clean it with a regular needle.

If your chain saw starts and shuts down right away, the chain may be malfunctioning. To correct problems check oil availability in the chain lubrication reservoir, and check the oil drain tube for lacerations or blockages.

STIHL 180 starts and stops the engine Reason.

When inspecting the piston group pay attention to the cylinder and replace it or the piston if necessary. The carburetor can be rebored to fit a new piston. If the piston and cylinder are normal, you should pay attention to the defects of the piston rings and the need to replace them.

Among other things, you should check the service life of the parts listed in the product passport, which include the drive sprocket, guide bar, chain, part of the anti-vibration system, to replace them in time.

It is worthwhile to check the condition of the fuel line if the instrument is idle for a long time. If the tube is cracked, it must be replaced with a new one.

Check filters and carburetor

Most chain saw breaks down if there is a problem with the filter or carburetor.

Checking the Fuel Filter

If the fuel filter is clogged with dirt, it is unable to pass a sufficient amount of fuel. As a result, the chain saw stops when you press the gas. Fuel burns too fast, and a new portion of it does not have enough time to enter the system. If a fuel filter is clogged insignificantly, there is a considerable power loss at maximum engine speed.

chainsaw fuel filter

Air filter

Contamination of this element makes it impossible to operate the chainsaw normally. But many models are equipped with a special compensator that takes in air in a different way. It makes it possible to do this even with a dirty filter, which has a positive effect on the machine’s performance.

stihl, chain, throttle

Chainsaw air filter and spark plug location

In such cases, the output of the saw will be noticeably reduced, but it will not stall. Sometimes a decrease in this characteristic is also observed when the piston is worn.

The carburetor

A common cause of malfunction with this type of tool is said to be carburetor failure. Checking this element is recommended to do with certain skills. It is better to have the appliance checked by a specialist, who will carry out a good diagnosis and adjustment using a tachometer.

This is particularly important if the saw stalls when idling. It is advisable to check the operation of the muffler. It is because of the accumulation of exhaust gases that the saw stalls at idle speed and does not work normally. It often happens that the saw has not been used for a long time. When it begins to operate again, notice that when starting at idle, the unit works well, and when you press the gas. it throttles. The main reason for this negative phenomenon is a jammed nozzle valve.

To check the presence of such a malfunction, it is necessary to remove and disassemble the carburetor. For this purpose it is necessary to unscrew two nuts, where the fastening of the air filter took place. It is removed together with the engine control lever. The choke control rod from the carburetor must be disconnected.

Removing the carburetor cover

In the next step, this detail should be pulled slightly towards yourself, disconnecting the hose for fuel supply. This should be done especially carefully, having previously prepared a special plug. It is useful for closing the hose, because the fuel will be released from it.

When the carburettor has been removed, it should be cleaned of dirt and blown on. Only then can you try to unscrew the part. You need to take out the main cover and with a small bolt you have to gently knock the valve out. It must allow air to pass only in one direction. If it runs on both sides. then it is necessary to replace this part.

Carburetor disassembled

What to do if the chainsaw stops when you press the gas

One of the most common questions about this device: why does the chainsaw quit when you press the gas and what do you need to do to solve the problem? In such a situation, it is necessary to perform the following actions:

  • Make a check of the fuel filter;
  • inspect fuel hoses for leaks;
  • Check the muffler;
  • try to increase the rpm a little;
  • Check the condition of the rubber seals on the crankshaft.

When the first signs of loss of power (loss of speed) of the KS 180 chain saw are detected, you should not continue working under any circumstances and should immediately contact a specialist or have the problem diagnosed and repaired yourself. There are not many reasons for the loss of power, and you can even deal with them, even without certain skills. The main thing is to calmly analyze the saw’s behavior and find out the reasons why it stopped pulling (speed has dropped), and it’s not easy to fix the malfunction anymore.

Modernization does not stand still. And the chain saws of the past that apart from being able to cut wood and emit a dreadful noise and vibrations audible almost miles away are long gone. Virtually silent, precise tools, which are now a pleasure to hold, have flooded the market, giving users a feeling of complete happiness and technical freedom.

But, unfortunately, no matter how technically and visually advanced the equipment is, its failure is a frequent occurrence, and the manufacturers talk about it only “by default”. Not an exception to this are chainsaws, multi-functional working machines that require a great deal of attention from the user in order to recognize the “catch” in time and stop the problem at the earliest possible stage.

The most important of these nuances are usually related to the start, which should be treated with the utmost responsibility. Let’s talk about the basic processes that can happen to a chainsaw when the engine is running.

How to use it correctly

How to use the power tool properly is described in detail in the documentation. The manual included with every chainsaw contains extensive information on proper operation, safe operating practices, and basic adjustments.

Working with a chainsaw begins with starting the engine. Starting a cold and warm engine has differences. When the engine is cold, the fuel evaporates badly and the mixture becomes too lean for normal performance. The carburetor air damper is controlled to enrich the mixture. Before the first start, the choke must be closed with a lever.

Start by pulling the starter rope quickly but gently. If the mixture shows signs of ignition, the air damper is opened and the saw is allowed to run for a few minutes at idle speed.

The instruction manual for the chainsaw does not recommend doing repairs yourself in case of malfunctions, but with experience in maintenance, most of the work can be done by yourself.

Why the chainsaw stalls, the main causes.

Although the chainsaw is not a complicated machine, it does occasionally malfunction and can only be repaired by disassembly. Examples of malfunctions are as follows:

  • The chainsaw does not pick up speed;
  • The chainsaw stops functioning in the cut;
  • chain saw starts and stops;
  • the chainsaw loses its power;
  • Your chain saw stops when you press.
stihl, chain, throttle

Most of the malfunctions are caused by the malfunctioning of the engine, but also by faults in other systems and components. Correct handling of the machine is important. If all the rules of usage are followed, problems are most likely to be the most obvious. When searching for the causes of trouble, it is advisable to begin by checking the simplest part of the chainsaw and end with the most complex.

Malfunctions that lead to improper chain saw operation

There are a number of faults that need to be taken into account when diagnosing, i.e. к. They can lead to malfunctions in the chain saw.

  • Worn crankshaft bearings. If the crankshaft bearings are worn, it is inevitable that runout will occur on the main shaft where the flywheel is attached. In this situation it is not possible to adjust the play between the handwheel and the ignition coil, which leads to an interruption of the spark formation and unstable operation of the chain saw.
  • Contamination of the impulse line. The impulse channel serves for ensuring operation of the fuel pump, respectively its contamination leads to improper operation of the pump, which will make it impossible to operate the saw (it will start and immediately stop).
  • Wear of the gas cylinder gear. As a rule, with increased wear of the cylinder, there is a decrease in compression in the chainsaw engine, which is bound to affect its ability to develop revolutions.
  • Contamination of fuel and air filters.

Gasoline saw stalls at high RPMs. a simple carburetor repair

The carburetor of the tool is the very mechanism that most owners are afraid to disassemble on their own. The reason is that this mechanism consists of many small parts, the location of which you need to remember when carrying out disassembly work. But all is not as terrible and difficult as it may seem. To understand what the carburetor has to do with the problem of the engine stopping at higher revs, you need to know its principle of operation, described at.

The chainsaw stalls when you press the gas because of the carburetor if:

  • The diaphragm is damaged
  • Clogging of filter element (mesh in carburetor). This malfunction can be encountered by the owners of tools that have no fuel filter or it is simply disconnected from the fuel hose

It is recommended to clean and wash your chain saw carburetor, and replace defective parts and components. After that you can put it back, not forgetting also to replace (if worn) the gasket between the carburetor and the adapter.


One of the reasons why the chainsaw doesn’t rev up when you step on the gas and instead stalls is that the carburetor malfunctions. Let’s assume the STIHL 180 was working properly and it has been put away for a long time without use. After you have started it, and it works fine at idle, but when you press the gas may stall. Why does it stall?? The cause is a jammed carburetor valve nozzle. This is not 100%, but the possibility of such a malfunction is high. Read an article about the device and repair the carburetor STIHL 180.

To be able to check the injector, you need to remove the carburetor and disassemble it. To remove, you need to unscrew the two nuts fixing the air filter and carburetor, then remove the air filter and engine control lever, disconnecting at the same time the control rod of the air damper from the carburetor. Next, you need a little pull the carburetor himself, and disconnect the fuel supply hose.

Need to very carefully remove the fuel hose, and in advance prepare a plug here, t. к. With his use should go fuel.

Removing the carburetor it must be blown and cleaned from the dirt, but then the carburetor of course unscrew.

You need to unscrew the cover of the main chamber of the carburetor, it is the one where the compensator is installed on top. Next, when using a bolt of 8 mm and a length of two or more than 50 mm. Knock out the valve.