What to do if a chainsaw stalls, what could be the reasons and how to eliminate them

Most common reasons

A chainsaw is considered a fairly simple and trouble-free tool, but it can suddenly stop working. The reasons why a chainsaw is difficult to start and stalls can be different: from low-quality gasoline to serious problems. Most often, you can find the cause on your own, but in some cases you will have to contact a specialist. It is important to remember that you cannot operate a faulty chainsaw.

Fuel mixture

The most common reason for failure is a problem with gasoline or oil. It is necessary to use fuel of the brand recommended by the manufacturer. When choosing oil, you should choose oils with special additives. Manufacturers usually recommend choosing AI-92 gasoline and two-stroke oil.

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

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

High-quality fuel is the key to long service life Source amazon.com

Filters

The reason why the chainsaw does not pick up speed and stalls may be a dirty air filter. It does not allow air to pass through in the amount that the tool needs for high-quality work. Initially, the carburetor is configured to mix a certain amount of incoming air and gasoline. When the filter is dirty, the amount of incoming air decreases, but the amount of gasoline remains the same. The result is an enriched mixture.

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

In summer, when the air is dry, use a cotton filter;
The HD2 filter is used when working in winter or in dusty conditions, for example, when logging large quantities of timber.

When the fuel filter is dirty, the situation is the opposite: the amount of fuel decreases and the mixture becomes leaner. The uniform supply of fuel is disrupted, and the chainsaw stalls when you press the gas.

Air filter for chainsaw Source drel-master.ru

Spark plug

When figuring out why the chainsaw stalls at idle, you should immediately check the spark plug. It is an important part of the tool. There may be several problems with it:

It may become filled with oil or fuel during the startup process. This happens especially often when inexperienced craftsmen do not follow the startup sequence. You need to unscrew the spark plug and let it dry or screw in a new one.
The candle may become covered with soot due to prolonged use. To prevent this from happening, the spark plugs must be cleaned regularly with a wire brush or fine-grit sandpaper. It is also worth changing the spark plugs regularly.
There may be problems with the spark plug tip. This is easy to check: you need to unscrew the spark plug and pull the starter cord. If a spark appears, then the spark plug and electronics are ok. If there is no spark, the problem may be due to depressurization of the pipes or a clogged fuel filter.
The problem may be due to a violation of the gap between the magneto and the ignition coil. The gap size is indicated in the instructions for the tool; on average it is 0.5-0.65 mm. The problem may arise from working in difficult conditions where the saw is subject to shock.

Spark plug filled with oil Source renault-portal.ru
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Breather

If the chainsaw does not hold idle speed, it is worth checking the breather. This is a small valve, a hole in the saw's gas tank through which air passes. Thanks to this, a vacuum does not form in the tank, and the tool works without interruption. The breather can be located in the tank lid or in the wall.

When the breather is clogged, a rarefied atmosphere is created inside. Because of this, gasoline does not pass into the carburetor. It happens that the primer (this is a pump for pre-feeding fuel) pumps a small amount of gasoline into the carburetor, and the chainsaw starts. But after the carburetor runs out of gas, the tool stalls because a clogged breather prevents fuel from passing through.

Carburetor

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

Problems may include:

The injectors, channels, filter, and jets are clogged. This is often due to low-quality fuel. The filter is not able to clean gasoline from impurities and debris, which leads to clogging of the jets. Gasoline stops supplying in the required quantity, or even stops supplying altogether. At the same time, the saw loses a lot of power and soon stops working completely. To fix the problem, you will have to disassemble and clean the carburetor.

Instrument disassembly may be required Source svenezia.co.il

If the chainsaw stalls when “hot”, it is worth checking whether the rubber seal in the accelerator pump is damaged. This leads to additional air entering (“suction”), which causes the speed to increase, and soon the tool stalls. The problem is solved by replacing the cuff. It happens that replacing the cuff does not solve the problem - air continues to “suck in”. If you cannot determine where the air is coming from, you will have to replace all gaskets and seals.
The accelerator pump needle began to stick. The cause may be wear and tear or foreign objects getting inside. The saw will stop starting or start turning off during operation.
The check valve needle does not fit tightly to the seat. In this case, the chainsaw will begin to stall when the load increases, it will work poorly and unstably, and the spark plugs will begin to flood. It is not possible to repair the needle; it is better to replace the entire carburetor.

The problem may also be due to improper carburetor adjustment.

How to restore functionality

Therefore, the procedure depends on exactly when the saw stalls:

Immediately after starting - there is too much oil in the fuel mixture. In this case, the octane number of gasoline decreases, and the saw operates only on suction.
When tilted , there is little fuel in the tank. The easiest way to solve this problem is to just add gasoline.
It starts with difficulty and immediately stalls - the spark plug is covered with carbon deposits or is flooded. The part needs to be turned out and washed. If the resin has already hardened, heat the candle with a lighter and then clean it. Just be careful not to damage the contacts. Then rinse the candle in gasoline and dry it. During this time, dry the cylinder by pulling the starter rope several times. Put the candle in place.
At idle speed , the muffler is clogged. You need to remove it from the tool, wash it with a fat-dissolving agent or gasoline, dry it and put it back in place. The saw stalls at idle also when the gap between the spark plug and the wire increases. Adjusting it will help solve the problem.

Each of the described reasons manifests itself at a certain stage of the instrument’s operation.

Immediately after starting work , the carburetor settings were lost. It can be adjusted at idle speed using bolts L and H.
At maximum speed - the fuel filter or breather is clogged. The filter needs to be replaced. Clean the breather with a thin needle.
Under load , the air filter is clogged. You need to take it out and blow it out to remove dust. In case of significant contamination, rinse and dry thoroughly.
It works exclusively on suction - the fuel pump is faulty. The part needs to be removed and checked to see if fuel is leaking. If gasoline is leaking, replace the gasket or replace the pump completely.
Stalls after heating - magneto malfunction. In most tool models, this part cannot be repaired and must be replaced.

Briefly about the main thing

A chainsaw is not a necessary tool in the household, but it greatly simplifies life in various situations. It is easy to use and easy to maintain, but at times the saw may stop working.

I've had problems several times. The first time, I, still an inexperienced master, mixed gasoline and oil in the wrong proportions and filled the spark plugs. I had to replace them completely because I bent the contacts while cleaning them. In the second, the chainsaw suddenly began to stall when heating up. I had to check the muffler and carburetor, then review all the gaskets and seals, and replace one of them.

I would like to give a little advice to everyone who has just started working with a chainsaw. If a problem arises, you should first check the oil and gasoline levels, the proportions of the fuel mixture, and only then climb inside. You also need to store the tool properly (be sure to drain the oil and gasoline for the winter) and regularly check it before use.

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Power system: incorrect fuel mixture

Two-stroke engines are designed to run on a mixture of gasoline and oil, which is needed to lubricate the cylinder-piston group. Lack of oil will quickly damage the tool and lead to major repairs.

In gas-powered tools from different manufacturers, the ratio of oil to gasoline is 1:40 or 1:50. This proportion must not be violated under any circumstances. If you pour more oil than necessary, this will lead to coking of the piston compression rings. They will lie tightly in their grooves, and the engine will lose compression and power.

The only exception is the tool running-in mode. In this case, the mixture is made 1:25 and is used for a short time, with minimal load.

Signs of an excess of oil in gasoline are as follows: the chainsaw stalls, smokes profusely, and does not develop power.

Why does the chain on a chainsaw jam?

The reasons why the chain on the chainsaw does not spin may be damage to the drive sprocket and burning of the tip of the saw guide. First of all, you need to inspect the clutch. If the drive sprocket exhibits uneven tooth wear, cracks, or other defects, the sprocket must be replaced.

If after this the chainsaw chain jams and breaks, then you need to inspect the tire. Burning of its tip, as well as any other part of the guide, leads to increased heating and displacement of the chain. While rotating on the bus, the headset shifted to the side gets wedged. This is evidenced by cases in which the chain stretches on the chainsaw precisely in those places where the operator had previously discovered that the guide was burning and melting.

The cause of blade burning is most often a breakdown of the lubrication system of the cutting set. In this case, it is necessary to carefully inspect the oil pump and also rinse it of debris or frozen lubricant.

The chainsaw engine turns off after reaching maximum speed

The power unit stalls at high speeds due to the performance characteristics of the electronic unit not meeting the stated requirements. Failure is more typical for budget chainsaws made in China.

The reason for refusal may be:

lack of fuel mixture in the float chamber due to valve sticking;
clogging of the fuel filter or the breather located in the fuel tank cap.

Read also: Soldering stainless steel at home with a gas torch

The power unit also stalls at high speeds due to a dirty air intake filter. The same symptoms are typical for a situation where the chainsaw started up in standard mode and stalled during the warm-up stage.

Why doesn't the chainsaw gain momentum?

In cases in which the gasoline saw being used is not able to consistently gain speed and spontaneously stalls when pressing the accelerator, you will need to carefully check the engine crankcase and carburetor. First of all, the operator must carefully inspect the components and make sure that they are not sealed. If a large amount of oil was found inside the crankcase or carburetor, then it is necessary to eliminate the leak inside the faulty unit.

The next reason why a chainsaw does not develop speed is a manufacturing defect or mechanical damage to the breather located inside the fuel tank. A vacuum may form in the fuel tank, which leads to a lack of fuel supply to the working cylinder of the power unit. Another cause of this problem can be deposits that have accumulated on the surface of the fuel cylinder. In this case, you need to remove the filter element and wash it in clean gasoline. If after this the chainsaw continues to stall under load, then you need to perform the following procedure: turn off the power unit of the chainsaw, remove the fuel tank cap and screw it back on. If after this the engine of the power tool starts to gain speed and after 5 minutes of operation it stalls again, then the cause of the breakdown is a faulty breather.

Another common reason for the lack of speed of the saw motor can be a thick layer of carbon deposits on the walls of the factory muffler. Tar deposits and ash will prevent exhaust gases from escaping, causing them to flow back into the engine compartment. As a result, the engine will begin to make strange sounds and lose speed greatly even with slight pressure on the accelerator.

Carburetor check and repair

The operating principle of a chainsaw carburetor.

If checking the ignition system, fuel filters, and muffler did not produce 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 body designed to set the minimum rotation speed, maximum speed and idle speed.

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

If adjusting the device does not restore normal operation of the instrument, you need to completely disassemble the device and inspect it. It should be understood that a carburetor is a rather complex device; if you lack experience, it is advisable to contact specialists.

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

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

To sum it up...

Definitely, every item we buy has its own expiration date and sooner or later it breaks, and it becomes a shame when the degree of its breakdown is so great that it cannot be repaired. But you must admit that quite often we are simply negligent in our use of technology (see about proper operation and how to properly cut down a tree so that it falls in the right direction), and when it stops working, then we try to find ways to fix the breakdowns, resulting in a huge number of services.

But remember that even though the equipment breaks down, we can extend its “life” . All that is necessary is to simply take care of it, break it in after replacing parts (read how chainsaws are broken in here) and keep its spare parts clean and tidy. And then, undoubtedly, it will serve for many more years. It is also important to use exclusively high-quality spare parts and “additives” (see attachments for chainsaws). Then your equipment will work smoothly, and you will simply forget what repairs are.

We also recommend that you familiarize yourself with the Shtil ms 180 chainsaw.

Why does a chainsaw stall when heating up?

The situation in which a chainsaw starts up when cold, but may stall while warming up, is familiar to many who deal with them. The main reasons for this behavior of the saw are as follows.

The ignition module (coil) is faulty. You can determine the malfunction by checking the spark first on a cold engine, and then on a hot one. If there is no spark on a hot engine, then you should try to fix the problem by replacing the ignition coil.
The chainsaw carburetor is not set correctly (fills the spark plug hot). You can determine the problem by how the saw starts when cold. If for a cold start it is not necessary to close the air damper, and the engine starts without a preliminary flash, then the fuel mixture is not formed correctly and after the engine warms up, the fuel floods the spark plug and makes starting impossible. The problem is eliminated by adjusting the carburetor.
The spark plug is faulty. 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.

Air filter dirty

It is quite easy to verify that the air filter is dirty. You just need to remove it and start the chainsaw without it - if the saw works normally, then that means it’s the problem and you just need to change it or wash it, depending on its type. And don’t be afraid that the chainsaw will work for some time without protection from dust - if there is no dust cloud around you, then everything is in order.

So, remove the air filter. To do this, you need to remove the cover from the top rear part of the chainsaw, which is attached either with screws, or simply with some kind of fastener that you just need to turn or snap off.

If the saw operates normally when the filter is removed after starting, it means it is dirty.

The air filter can be felt or nylon. The first resembles cotton wool or padding polyester, and the second looks like a fine mesh of nylon threads stretched over a plastic body. The felt one needs to be replaced with a new one, but the nylon one can simply be washed in soapy water, dried and put back in place.

Nylon filterFelt filter

Well, we can continue to calmly use the chainsaw.