The Chainsaw Stalls Under Load

Why the chainsaw starts up and immediately stalls

The chainsaw starts up and immediately stalls, the reason for this behavior may be hidden in the carburetor. A malfunctioning fuel pump or malfunctioning of the main fuel jet can be a prerequisite for this behavior of the saw. The inability to operate the chainsaw after starting, requires a full diagnosis at the service center.

All of the above options for engine malfunction have similar reasons, which, depending on their neglect, may have different manifestations. For example, with a slight intake of air into the crankcase of the engine, its operation will not change much, the engine power will drop slightly, its maximum speed will increase, and it will be able to heat up a little more. In the middle stages of air leakage, the engine will stop idling and will get very hot during operation. Strong air leakage will make it impossible for the saw to work, it will start and immediately stall.

In parallel with the visible manifestations of malfunctions, for example, the inoperability of the chainsaw after starting, inside the engine at the time of its malfunctioning, there will be processes that irreversibly lead dust to the most severe consequences, for example, piston melting, crankshaft seizure.

Malfunctions leading to improper operation of the chainsaw

There are a number of faults that must be taken into account when diagnosing, since they can lead to interruptions in the operation of the saw.

  • Worn crankshaft bearings. With worn out crankshaft bearings, runout is inevitable on the main shaft, where the flywheel is attached. In such a situation, it is impossible to adjust the gap between the flywheel and the ignition coil, which entails interruptions in sparking, and unstable operation of the chainsaw.
  • Impulse channel contamination. The impulse channel serves to ensure the operation of the fuel pump, accordingly, its contamination leads to improper operation of the pump, which will make it impossible for the saw to work (it will start and immediately stall).
  • CPG wear. As a rule, with increased wear of the CPG, there is a decrease in compression in the engine of the chainsaw, which will necessarily affect its ability to develop speed.
  • Dirty fuel and air filters.

The chainsaw starts and stalls cause

Chainsaw owners sometimes have to deal with the fact that the saw, for no apparent reason, stops working normally. To understand why the chainsaw stalls under various operating modes, and also to describe how you can diagnose a malfunction, we will try in our article.

Why does a chainsaw stall under load

In some cases, the chainsaw, under load, is unable to work normally and simply stalls. A common reason for this behavior is improper carburetor adjustment, or air leaks through the crankshaft oil seals or carburetor gasket. And also this behavior can occur due to leaks in the carburetor.

A saw that is unable to operate under load will also be unsteady at idling. They will “float”. Diagnostics begins with a check for leaks in the crankcase and carburetor. If air leaks through the crankshaft oil seals, they must be replaced. If air leaks into the carburetor, the cause can be eliminated by installing a repair kit of gaskets.

The Chainsaw Stalls Under Load

Only after the above steps have not yielded results and the crankcase with the carburetor is sealed, you can start adjusting the carburetor.

The reason for this algorithm is as follows, if air leakage from the crankcase is NOT eliminated, but the carburetor was simply adjusted to normal engine operation, then the fuel mixture will contain more fuel than is required with a sealed crankcase, which in turn will significantly increase its consumption. Also, most likely, carbon deposits will appear in the engine, which will also negatively affect the further operation of the chainsaw.

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

, which shows how to replace a defective impulse hose with your own hands on a HUSQVARNA 142 chainsaw, can be seen below. It shows step by step the process of disassembling the saw, shows the impulse hose and discusses the consequences of its malfunction HUSQVARNA 142.

Why does a chainsaw stall when heated

The situation in which a chainsaw starts up on a cold one, and in the process of heating it can stall, is familiar to many who deal with them. The main reasons for this behavior of the saw are as follows.

  • Defective ignition module (coil). The fault can be determined by checking the Spark first on a cold engine, and then on a hot one. If there is a spark on a hot engine, then it is worth trying to fix the malfunction by replacing the ignition coil.
  • The carburetor of the chainsaw has an incorrect setting (fills a hot candle). The problem can be determined after the saw is started to cold. If for a cold start it is NOT required to close the air damper, and the engine starts without a preliminary flash, then the fuel mixture is formed incorrectly and after the engine warms up, fuel fills the spark plug and makes starting impossible. The problem is eliminated by adjusting the carburetor.
  • Spark plug defective. In such a situation, similar to a faulty ignition coil, the spark disappears when the engine heats up. It is worth trying to replace the spark plug with a new one, and if this does not help, then you need to check the ignition coil and the gap between it and the flywheel.

Algorithm for checking the crankcase for leaks

  • Remove the side cover and tire from the chainsaw.
  • Unscrew the spark plug and put a lace with knots in the cylinder through the spark plug hole, thereby stopping the movement of the piston and crankshaft.
  • As a lace with knots, you can use the old cord from the starter, put knots on it every 3-5 cm.
  • Spin the chain saw drive sprocket.
  • Remove the oil pump cover and the pump itself.
  • Remove the starter from the chainsaw.
  • Unscrew and remove the flywheel.
  • Remove carburetor.
  • Using a syringe, through the hole for the carburetor in the cylinder, pour gasoline into the crankcase, while observing the crankshaft oil seals. If gasoline flows through them, then the oil seals have become unusable and must be replaced with new ones.
  • It is better to entrust the installation of oil seals to professionals.

Air filter dirty

It’s easy to make sure the air filter is dirty. You just need to remove it and start the chainsaw without it. If the saw works fine, then it’s in it and it just needs to be changed or washed, depending on its type. Don’t be afraid that the chainsaw will run for a while without dust protection. If there is a dust cloud around you, then everything is fine.

So, remove the air filter. To do this, you need to remove the cover from the rear upper part of the chainsaw, which is fastened either with screws, or just some kind of lock, which you just need to return or snap off.

If the saw works normally when the filter is removed after starting up, then it is dirty.

The air filter is either felt or nylon. The first one looks like cotton wool or synthetic winterizer, and the second looks like a fine mesh of nylon threads stretched over a plastic case. Felt needs to be changed to a new one, but nylon can be simply washed in soapy water, Dry and put in place.

Nylon filter

Felt filter

Well, then we calmly use the chainsaw.

Low oil in the fuel mixture

Let’s look at the most unpleasant case first. Why? Because before manipulating the filters, it is better to make sure that your oil and gasoline are mixed in the correct ratio.

Here, however, it is worth noting that if your saw has already been turned on many times (for example, ten times), but it continues to start, and then stalls again when the speed increases, then apparently everything is in order with the fuel. Otherwise, she would have simply stopped starting altogether.

But still, I recommend that you immediately dispel the slightest doubts about the quality of the fuel, as soon as your saw stalled when you accelerate for the first time. Because, if the reason is in the fuel, then, as mentioned above, you can get expensive repairs. Otherwise, you can still do it. Dispel doubts. This is to drain the old fuel from the tank and fill with freshly prepared fuel, in which oil and gasoline are mixed in the correct proportion.

The correct ratio is best seen in the instructions for the saw. If you have lost it, then we look at the ratio on the oil package. It is usually 1:50 or 1:40. If the oil is used “non-native” (well, for example, for Stihl chainsaws, Stihl will also be a little “native”), then I recommend using a ratio of 1:40, even if the oil packaging says 1:50.

For accurate dosage, I myself personally use a medical syringe and a measuring container in which one liter of gasoline can be clearly measured. I pour a liter of gasoline into a container, draw 25 (at 1:40) or 20 (at 1:50) cubes of oil into the syringe and add it to the gasoline.

After preparing a new mixture, Drain the previous mixture from the tank, in which we are unsure, and fill in the fresh one we just Prepared.

Now that you have done everything to dispel any doubts about the quality of the fuel, we proceed to further actions.

As I wrote above, if there is a lack of oil, seizures can form on the piston and cylinder walls. over, they are almost always formed. If you are lucky and no seizure appears, then with the new fuel mixture, prepared in the correct ratio, the chainsaw should start working normally.

If seizures appear, then the saw can start several more times and stall, after which it will stop starting altogether. In such a situation, I sympathize with you, because, most likely, now you will need to replace the piston group, which will be very expensive.

If the saw, as before, starts and stalls at high speeds, then we manipulate the filters.

Why does the chainsaw stall when you press the gas?

Hello! If you find yourself on this page, then, most likely, your chainsaw stalls when you press the gas, and you want to know why this is happening and what to do about it. Well, I will try to help you with this problem by examining the most common causes of such a misfortune, as well as methods of eliminating them.

To begin with, I will immediately write for novice users that many chainsaws require warming up the engine idling for about one minute before work. While the engine is NOT WARMING up, the saw may stall when gas is added.

So, if a heated chainsaw can idle, but stalls under load, then this means that:

  • Incorrectly adjusted or clogged carburetor. The most common case;
  • She lacks air, the consumption of which increases sharply with increasing speed. This means that the air filter is dirty (a rare case, as the filter becomes dirty gradually, so the user first notices a loss of power);
  • It lacks fuel, the consumption of which also increases with increasing revs. This means that the fuel filter is dirty (also an infrequent case)
  • Well, the most unpleasant case is if there is excessive friction between the piston and the cylinder wall, associated with a lack of oil in the fuel mixture. After such a work of the chainsaw, you will most likely fly into the repair of the piston group, since scuffs form on the piston and cylinder walls that impede the operation of the saw.

Let’s analyze these cases separately.

Fuel filter dirty

If the option with an air filter did not suit you, then we try to change the fuel one. It is located in the gas tank and is attached to the hose, through which fuel is taken from the tank.

This hose must be gently pryed off with something and removed from the gas tank its edge, on which the filter is fixed. Here is an option with work without a filter, as in the case of an air filter.It is better not to use it, since you cannot know for sure if there are any unnecessary impurities in the fuel.

Fuel filter

Therefore, we simply change the fuel filter to a new one and try to work. If everything is ok, then congratulations. You found the reason.

Cleaning and adjusting the carburetor

If all of the above did not help, then, most likely, adjustment or cleaning of the carburetor is required. It is not recommended to do these procedures on your own, since most often such attempts still end with a trip to the service. So it’s better to go there right away and DO NOT disassemble anything on your own. But if you still want to dig deeper yourself, then it is best to look at which shows how experts do it:

I will end on this. Thanks for your attention! Read more articles on this site! Until next time!

Why the chainsaw stalls

There are several reasons why a chainsaw stalls. And, as a rule, almost all of them are solved independently, without going to the service center.

First of all, check the filters: fuel and air. If they are clogged, then, for sure, this is the reason for the improper operation of the tool. over, the dirt is not always visible to the naked eye. Therefore, even if everything seems to be in order, it is better to carry out this procedure.

The second reason is perhaps a candle. Remember when you changed it the last time? According to the rules for the operation of chainsaws, this should be done once a year.

If this does not help, then it is worth trying to adjust the carburetor. It is possible that vibrations when working with a chainsaw lost its factory settings.

If the saw stalls after long-term storage, for example, in an unheated garage, then it is worth looking at the fuel line. Usually, this is a rubber tube, which can crack from dampness and temperature drops and the floor is a prerequisite for a chainsaw malfunction.

If none of the above helped, then, most likely, the breakdown is more serious, and, unfortunately, you will have to contact the workshop.

Chainsaw stops idling

Firstly, it is recommended to check the muffler, as its contamination can lead to a deterioration in the exhaust gas output, which is why the engine stops.

If cleaning the muffler does not solve the problem, and your saw engine is carbureted, then you can try to tune it. Most engine models have coarse and fine adjusting bolts (H and L respectively). Using them to increase engine speed can eliminate the problem. Be aware that the carburetor adjustment. This is a rather delicate process that requires the use of a tachometer.

Problems of the fuel and air filters and their elimination

The chainsaw will shut off at idle speed if the fuel or air filter becomes clogged. Disconnect the fuel lines from the carburetor to find out the condition of the first element of the fuel system. If, during pumping, the fuel is supplied in doses corresponding to the specified rates, then the cause of the malfunction should be looked for elsewhere. If gasoline enters the carburetor weakly or does NOT flow out of the hose at all, then most likely the filter is clogged with debris.

To clean it, remove it from the tank (from the container until this moment it should be Drain all fuel). Extraction takes place 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 there is such a possibility or it is impractical to do it for a number of reasons, the used filter is replaced with a new one.

Chainsaw may stall if fuel filter becomes clogged.

The air filter can also be clogged with dirt or dust, resulting in malfunctions at idle. It should be remembered that clogging of this filter occurs quite often, as a result of which it becomes difficult for air to enter the system. The proportion of gasoline in the fuel-air mixture increases, and it turns out to be too rich. In this case, normal engine operation should not be expected.

For cleaning, the air filter is removed with special care so as not to shake off the dust into the carburetor. Then it is cleaned and thoroughly washed. 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.

Chainsaw stalls when rpm increases

The reasons for this phenomenon are similar to the previous ones: either the problem is in the fuel system, or in the air filter. Try disconnecting the fuel hose from the carburetor. If gasoline does not flow well (but you know for sure that there is fuel in the tank), then the reason is in the gasoline filter. You can, at the same time, check the fuel pump. Fuel must not seep through it. If this happens, then it is advisable to replace the pump.

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 housing, mechanical damage, flow 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 sudden fluctuations in air temperatures, this tube could simply crack. This fuel line is NOT suitable for further use and should be replaced.

Another prerequisite for which a chainsaw may stall at idle is non-compliance with the ratio of ingredients when preparing the “fuel mixture”. The proportions of gasoline and oil included in it must exactly match the manufacturer’s instructions for a particular device. If they are not observed, the engine will not lubricate sufficiently and the whole mechanism will stall persistently.

Why does a chainsaw stall under load

The reasons why the chainsaw starts and stalls

A chainsaw has long been NOT a luxury, but a necessary tool for those who have a summer cottage or home ownership. But, like any other technique, this tool tends to fail, despite the simple device.

The classification of the main faults includes:

  • Complete absence of engine plant
  • Engine starts and stalls
  • Unstable tool performance
  • Stop under load
  • Loss of power.

If the chainsaw does not start at all, the reason may be:

  • Manufacturing defect
  • Lack of fuel
  • Problems with starting the ignition system
  • No spark from spark plugs
  • Poor fuel mixture
  • Carburettor clogged
  • High voltage wire problems
  • No compression.

Why does the chainsaw start and stall, what to do in this case? The reasons for this need to be considered in detail.

The chainsaw starts and stalls: the reason,

The reason that the chainsaw can stall right after the factory lies in the malfunction of a certain part of the equipment.

  • The most commonplace reason for why the chainsaw started up and stalled may be the low fuel level in the tank. This can be confirmed by stopping the operation of the tool when tilting, when fuel residues accumulate in a certain place in the fuel tank. With poor fuel, there may also be a problem with the operation of the chainsaw, in which case you need to completely replace it.
  • Clogged breather, which significantly reduces fuel consumption to the engine.
  • The contact of the wire cap with the candle is insufficient, which leads to strong heating of the spark plug insulator. Deterioration of contact can occur due to mechanical shear or carbon deposits.
  • Broken spark plugs.
  • Clogged muffler, which leads to poor exhaust gas discharge, leading to engine shutdown. For this reason, the chainsaw can start and stall at idle speed. Sediment in the muffler can also appear due to poor-quality fuel or improper operation of the tool.
  • Poor carburetor adjustment.
  • Breakage of the piston group
  • Fuel filter or pump problems. In this case, gasoline may flow through the pump or poorly flow through the fuel filter to the carburetor. In total, the chainsaw starts up and stalls when the speed increases.
  • Dirty air filter. Problems with this piece of equipment lead to the fact that with increased engine loads, it simply cannot cope with them due to blockage and stops. A similar result is also obtained with an increase in speed.
  • Short circuit due to lack of or insufficient lubrication, or a problem with the chain brake.

Why the chainsaw does not start well and stalls

With a poor start of the equipment “to cold” the problem may be in the absence of compression, ie. The rings are worn out due to a long service life, they need to be replaced. Sometimes a problem with the muffler, as well as poor contact between the spark plug and the manual, is a prerequisite for the engine to start poorly in the not very warm state.

Also, the reasons for a poor start can be wear or damage to the gasket, rubber cuff in the accelerator pump of the carburetor, which causes an additional air flow, leading to an increase in saw speed.


The operation of the equipment must be correct, with periodic inspection of the constituent elements to prevent damage. To troubleshoot, it is necessary to check all components of the equipment for their functioning.

If the chainsaw starts and stalls, the cause can be eliminated on your own. If it is a shortage or improperly prepared fuel mixture, it is necessary to correct it. For prophylaxis during the idle time of the chainsaw, you should always drain the remaining fuel.

The spark plugs should be checked periodically. In this case, remove carbon deposits that clog the joint gap, and also check the tips for the presence of fuel. Another prerequisite for problems with spark plugs can be wetting with gasoline. To do this, they need to be removed, wiped off with a rag and left to dry. Defective spark plugs are replaced.

If there is no spark between the spark plug and the high-voltage wire, but if there is a good connection, the ignition unit must be replaced.

A clogged muffler is a common prerequisite for breakdowns, in which the chainsaw starts and immediately stalls. To eliminate the malfunction, you need to dismantle the muffler, clean it from carbon deposits using sandpaper or a special chemical solution. If the model of the chainsaw is non-separable, chemicals are poured into the system and are there for several hours, then it is blown.

The carburetor must be adjusted if the chainsaw stalls at idle speed. Fine tuning is a rather laborious process, so it is usually done in service centers. But, on some models there are elements for adjusting it, it is enough to return the bolt half a turn to increase the speed of the chainsaw, the problems will be eliminated. If the jets, nozzles, channels and filters are clogged, it is necessary to disassemble and clean the entire carburetor. When oil seals, gaskets, cuffs are worn out, it is necessary to replace them, preventing air leakage.

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

If the breather is blocked, it must be cleaned with a regular needle.

When the chainsaw starts up and immediately stalls, the reason may lie in the malfunctioning of the chain. To troubleshoot problems, check the presence of oil in the chain lubrication container, as well as the oil return pipe for breaks or blockages.

When inspecting the piston group, pay attention to the cylinder; if necessary, replace it or the piston. The cylinder can be bored to fit the new piston. If the piston with the cylinder is normal, pay attention to the defects of the piston rings and the need to replace them.

Among other things, you should control the service life of the parts specified in the product passport, which include the drive sprocket, tire, chain, part of the anti-vibration system, and replace them in time.

If the tool is idle for a long time, it is worth checking the condition of the fuel line. If the tube is cracked, you will have to replace it with a new one.