Chainsaws: the meaning of the main technical characteristics

Situations in which adjustment is necessary

New chainsaws are supplied by the manufacturer with already adjusted carburetors. This is called standard adjustment. But for the normal running-in process, it is necessary to reduce the maximum engine speed and adjust the carburetor. After break-in, the chainsaw needs fine tuning to achieve maximum engine efficiency.

Also, a signal for cleaning and adjustment is increased fuel consumption, which negatively affects the operation of the exhaust system. Simply put, the chainsaw begins to smoke heavily and the muffler becomes clogged with carbon deposits, which in turn will lead to a decrease in power.

If there is too much fuel in the mixture, engine parts are poorly lubricated and premature wear occurs. Also, a poor quality mixture can cause the engine to jam due to overheating (this is one of the reasons why the chainsaw will not start).

This is what a jammed, overheated piston looks like from a disassembled chainsaw with an incorrectly configured carburetor.

Adjustment is necessary when the engine does not idle, stalls, or does not develop full power. Carburetor adjustment should be carried out with clean air and fuel filters. We also recommend reading an interesting article that details the main reasons why a chainsaw starts and immediately stalls.

What to consider when choosing a chainsaw

When choosing and purchasing a tool such as a chainsaw, it is advisable not only to look at the characteristics and additional devices, but also to hold it in your hands or even start it. Convenient holding in the working position and during transfer, absence of vibration, low noise, effort when starting - this can only be checked by “communicating” with the saw directly. But you need to start choosing a chainsaw, of course, with the passport data.

Power

The main attention when choosing is the engine power. Not only that, it is the power that determines the capabilities of the saw itself. Many other parameters directly or indirectly depend on it - dimensions, weight, volumes of filler tanks, engine starting system, fuel consumption, service life of the entire tool.

On the one hand, it seems that increased power will not be superfluous, but on the other hand, why is it needed if the intended work can be performed with a weaker saw. Nobody needs extra expenses and problems. Therefore, you need to choose a good chainsaw with an idea of ​​how powerful it should be.

It is worth paying attention to the ratio of the volumes of the fuel and oil tanks. If the chain lubrication tank is 1.5–2 times smaller than the fuel tank, then they empty in about the same time.

Tires and chains

The maximum depth of cut that can be made depends on the size of the guide bar. But the use of long tires creates additional load on the engine and causes increased vibration. Chainsaw data sheets indicate the recommended tire length for a given model.

Note! Installing a tire of a shorter length will not create any problems, but installing a tire longer than recommended is undesirable and often dangerous.

On household and semi-professional models, the length of the tires does not exceed 40 cm, on professional ones it reaches 75 cm.

The length of the chainsaw chain naturally corresponds to the length of the selected guide bar. In addition to length, chains are also characterized by the pitch of the cutting links, their size and sharpening profile. The pitch is measured in fractions of an inch and has standard values ​​of 0.325; 0.375 and 0.404. To avoid confusion with the similar numbers 0.325 and 0.375, the latter value is often quoted as 3/8 inch.

The chain pitch affects the performance of the saw - the smaller it is, the more difficult it is to cut. But an increase in step is accompanied by an increase in vibration. Therefore, large pitch chains are used in professional models. For domestic needs (at the dacha, near the house), a step of 0.325 is selected.

For chainsaws, the “manufacturer’s triad” must be observed - the saw itself, the bar for it and the cutting chain of the same brand. It is unlikely that it will be possible to install a tire from another manufacturer on a saw.

Oil pump

Reliable lubrication of the bar and chain during operation reduces cutting efforts and significantly extends the life of the chain. The oil pump is responsible for supplying oil. It is worth paying attention to its characteristics. The pump housing can be made of metal or plastic. Metal is more expensive, but more reliable.

In professional and semi-professional types of chainsaws, pumps with manual adjustment of the oil supply can be installed, allowing you to use it more economically. In household models there is no such adjustment.

Additional features and devices

Some of these devices are designed for ease of use, while others directly affect the health and safety of the employee. When purchasing, it would be a good idea to inquire about their availability on the selected model.

Easy engine starting. Additional devices that help start the engine are a fuel pump before starting, a decompression valve, and a spring starter. On models with a spring starter, there is no need for a sharp tug on the starting cord. Pulling the cord simply cocks the spring, which, when released, turns the starter.

Reduced vibration. Prolonged work with a tool that transmits vibrations to the worker’s hands can lead to unpleasant sensations and, over time, to chronic illness. All manufacturers strive to reduce vibration in their instruments. In domestic models, where vibration is already low, rubber gaskets are used to reduce the transmission of vibrations from the engine to the handles. Special damper systems are installed in professional chainsaws.

Protective functions. The main one is protection against kickback, which throws the saw to the side. Having protection against it is a prerequisite for safety at work. This may be a casing that covers the upper part of the bar with a chain, but more often it is a safety lever that blocks the movement of the chain during a reverse impact. An additional protection mechanism is a double lever for starting the movement of the chain ("gas" lever). If at least one of them is not pressed, the movement of the chain stops. A third protective device, a toothed chain catcher, can protect a worker in the event of a chain break.

Tools

To adjust, you will need the following tools: tachometer, screwdrivers, and in rare cases, special keys. Let's look at their purpose, necessity of availability and cost.

If possible, setting up a chainsaw should be carried out in official service centers that have a manufacturer’s certificate and appropriate permission to carry out repair work.

Gasoline and oil for work

As already mentioned, chainsaws are not fueled with pure gasoline, but with a mixture of gasoline and oil. The recommended proportion of oil in gasoline must be indicated by the manufacturer. The working ratio is from 1:25 to 1:40.

The oil for preparing the mixture is also specialized. And if for chainsaws of domestic brands you can use universal oil for two-stroke engines, then for expensive imported models you need to purchase special oil from the same manufacturer. It's better not to save money on this.

It is not recommended to store gasoline diluted with oil for more than a month. The properties of gasoline mixed with oil deteriorate over time.

The requirements for chain oil are not so strict. Almost any mineral oil will do, although oils specifically for chain lubrication are commercially available. But in winter, you need to switch to synthetic types of oil, which thicken less in the cold. You should absolutely not use used oil for lubrication.

How is the carburetor adjusted?

The chainsaw setup algorithm is quite simple and consists of the following steps:

1. Warming up the engine to operating temperature ( the adjustment must be carried out only on a warm engine , this will allow for more accurate adjustment).
2. Adjusting the engine for smooth operation at low speeds.
3. Setting the carburetor to properly supply the fuel mixture at maximum speed.
4. Precise adjustment of the carburetor for idle operation.
5. Checking the chainsaw in all modes.

Almost all carburetor models have three adjustment screws.

• Screw (T) is responsible for fine adjustment in idle mode.
• Screw (H) adjusts operation at maximum speed.
• Screw (L) regulates mixture formation at low speeds.

By tightening screws (L) and (H), the fuel supply and mixture become leaner, and the speed increases accordingly.

Carburetor adjustment screws L - minimum speed and H - maximum engine speed.

Now let’s look at how to properly adjust a chainsaw carburetor in more detail.

About the carburetor design

The carburetor serves to mix the flammable mixture with air while maintaining predetermined proportions. If clear doses are not followed, the proper operation of the engine is at risk. When a huge amount of air enters during mixing of the components, but there is not enough fuel, then such a mixture is considered “lean”.

Oversaturation should not be allowed, because with a larger amount of fuel compared to air, malfunctions or engine wear are also likely. Carburetor adjustment is needed not only before initial use, but also when any differences in its operation are detected. Before starting to work with a chainsaw, do not forget to run it in.

Carburetor components

The carburetor design contains a standard set of parts, but may vary slightly depending on the manufacturer. Components:

1. The basis . This is a special tube that is visually similar to an aerodynamic design. Air passes through it. In the transverse direction, a damper is located in the middle of the pipe. Its position can be changed. The more it is extended into the passage, the less air enters the engine.
2. Diffuser . This is the constricted part of the tube. With its help, the air supply speed increases precisely in the segment from which the fuel comes out.
3. Channels for fuel supply. The fuel mixture is contained in the float chamber, then passes into the nozzle, from which it flows into the atomizer.
4. Float chamber . It is a separate structural element, reminiscent of the shape of a tank. Designed to constantly maintain the optimal level of fuel fluid before entering the channel from which air enters.

Don't know which chainsaw to choose?
Read our article. Are you looking for cheaper models, but reliable and time-tested? Pay attention to Russian-made chainsaws.

Or explore foreign chainsaw manufacturers such as Shtil.

Process description

1. If the chainsaw carburetor is not adjusted and it is not possible to start the chainsaw, then the adjustment begins by installing screws (L) and (H) to the standard setting position. This is 1/5 turn of the screws until they are fully tightened.
2. After which, you need to start the engine, let it run a little and warm up.
3. The next step is setting the low speed mode. Optimal engine operation at low end can be achieved by adjusting the screw (L) and idle speed (T). To do this, first screw (L) is tightened until maximum engine speed is reached, then released by 1/4, and screw (T) is used to return the idle speed to normal.
4. After adjusting the operation at the “lower” range, the traction and maximum engine speed are adjusted. To do this, slowly tighten the screw (H) and check the speed using the readings of the electronic tachometer. It is unacceptable to exceed the maximum engine speed declared by the manufacturer! The ideal option for this would be to use an electronic tachometer, which can be bought at a low price on Aliexpress.

Buy tachometer on Aliexpress

Location of carburetor adjustment screws on a Husqvarna chainsaw.
An important step is to check the saw in all operating modes after adjustment; to do this, you need to let the chainsaw cool, and then start it according to the cold tool starting algorithm. If the saw starts up normally and idles smoothly, you need to check how it cuts. If during the inspection process shortcomings in the power of the chainsaw are discovered, then it is necessary to repeat the adjustment of the screw (H) by unscrewing it and checking the traction in operation.

Loss of traction at the maximum speed recommended by the manufacturer is an indicator of CPG wear or poor fuel quality. Speaking of fuel, 90% of malfunctions are caused by fuel. Which one should I use? 92 or 95? How long can it be stored? We answered all these questions in the article about what kind of gasoline to put in a chainsaw.

We recommend watching a video on how to clean and adjust a chainsaw carburetor, the author of which also talks about the harmful effects of fuel on the components of the carburetor. The example shows how to restore your carburetor using an inexpensive repair kit.

Chainsaw categories

To choose a tool, you need to be based on a clear idea of ​​the type and quality of work performed with it. Chainsaw is no exception. The more accurately you know the planned work using a saw and its volume, the easier it is to choose a specific model.

According to the types of work for which they are intended, chainsaws are divided into three categories: household, semi-professional and professional. Comparisons of models from different companies can be carried out within the same category. They are distinguished mainly by engine power, continuous operation time and total resource.

Household or amateur

Designed to perform simple and short-term work in the country or near your home - pruning garden trees, preparing a small amount of firewood, simple processing of wooden products or buildings. Small size and weight do not require much physical effort during operation. Evil tongues call such models female. And they are truly available for use by anyone. They place great importance on additional characteristics - reduced vibration and effective noise suppression. In terms of cost, this is the most inexpensive type of chainsaw.

Parameters of this class:

• power less than 2 kW;
• weight 4–5 kg;
• typical duration of continuous operation is half an hour;
• total motor life is about 400 hours.

Among the popular models of this category of chainsaws, you can choose the ALPINA A 3700, which is quite affordable. Husqvarna brand saws have proven themselves well. (Hitachi) also has a small model - CS33EB, which is included in the rating of the best, which can be chosen for its lightness, low vibration, and economical fuel consumption.

Semi-professional or farm

This is already a serious tool, capable of performing long and complex work. It is worth choosing for any sawing work on the construction and maintenance of a country house. Regular procurement of firewood for stoves and fireplaces, felling of small trees on the site, almost any work related to cutting and high-quality processing of wooden structures. Models of this class are most often chosen by teams building wooden log houses. They are used in logging sites to clean trees from branches and twigs.

But the dimensions and weight of these tools already require increased physical effort and work skills.

Their parameters:

• power up to 4 kW;
• weight 5–8 kg;
• designed for continuous operation for 4 hours;
• total motor life – 1000 hours or more.

Here it is worth highlighting the Husqvarna 445, 450e, 61 chainsaws. Below them in price is the Daewoo DACS 5218 saw, which you can choose with peace of mind. There are also several semi-professional models "Calm" (STIHL).

Professional

Already from the name it is clear that this type of chainsaw is designed to perform long and difficult work on felling large trees. High power, with extended guide bars, designed to work in all weather conditions, they require significant physical effort from the worker. Typically used in logging. It is unprofitable to purchase a saw of this class even for a large household - there is simply no suitable scope of work for it.

Options:

• power can be 3 kW or more, reaching a value of 9 kW;
• weight – up to 15 kg;
• continuous operation for 10–12 hours;
• The total service life is several thousand hours.

Professionals usually know by what parameters they can choose the best model. Many well-known companies produce such chainsaws. Stihl MS 880-36, 661, Makita DCS 7301-50, Husqvarna 576XP-18 have proven themselves well.

Adjusting the carburetor of a Chinese chainsaw

Carburetors installed on Chinese-made saws are made similarly to European ones and have the same adjustment screws.

Adjusting the carburetor of a Chinese chainsaw follows the algorithm presented above, and differs in that when initially adjusting the screws (L) and (H), they must be turned out two turns. Next, the carburetors of the Chinese saw are adjusted in the same way as European ones.

Read about how to adjust the carburetor of a Chinese chainsaw in just 3 steps here (a very useful article). As an example, we recommend looking at the article about adjusting the carburetor on a Carver chainsaw.

How to make a tachometer for a chainsaw with your own hands

Making a tachometer for a chainsaw with your own hands is rational only if there is a single need for its use. If you are a regular owner of gas-powered tools, then it is recommended to acquire a factory-made device. Multifunction multimeters have a frequency measurement mode that can be used to calculate revolutions.

You can make the device yourself, but for such purposes you will need a soldering iron and some electronic consumables: resistors, diodes, capacitors. The head from a tape recorder is used as a speed indicator.

The video shows the finished device in action. The only drawback of such a device is low accuracy, as well as the need to calculate the number of revolutions, since the device displays decibels.

If you need to get the most accurate results for setting up a chainsaw, then experts recommend using factory tachometers (even if they are of Chinese origin).

STIHL MC 180 chainsaw – technical specifications

In terms of performance indicators, chainsaw is in many ways superior to analogues in its price category. This tool, as well as its modification – chainsaw , has the following technical characteristics:

• Power – 2 l. With.;
• Cylinder displacement – ​​31.8 cm3;
• Fuel consumption – 0.7 l/h;
• Fuel tank capacity – 250 ml;
• The volume of the oil supply tank is 145 ml;
• Idle speed – 2800 rpm;
• Launch – manual;
• Chain lubrication – automatic;
• The length of the tires used is 30–35 cm;
• Chain pitch – 3/8''v
• Operating weight: 4.2 kg.

chainsaw does not require special care. The only thing the owner needs is to use high-quality fuel and add oil on time. The diameter of the file for sharpening the STIHL MS 180 chainsaw chain should be 4.5–5 mm.

Sources:

https://decor-skinali.ru/skolko-oborotov-u-benzopily/

Checking acceleration operation

Need to do a little research. Acceleration of the device is initiated. It is necessary to evaluate the proper operation of the engine during maximum speed. When the engine is functioning correctly, it means that when you press the accelerator, the speed quickly increases to 15,000 rpm.

If this does not happen or the increase in speed is too slow, you must use the screw marked L. It turns counterclockwise. Moderate movements must be observed, since the turn cannot be more than 1/8 of a full circle.

How to set the ignition on a Partner chainsaw?

Before setting the ignition, you will need to make sure that the spark plug is working properly. If it is not filled with the fuel mixture, and no traces of soot are visible on it, then you can start tuning. All subsequent actions boil down to adjusting the gap between the flywheel and magneto. The algorithm of actions is as follows:

1. First you need to take measurements of the current gap between the two elements. For stable operation of the ignition system, it should be no more than 0.2 mm. If the gap is too large, then it needs to be adjusted;
2. To do this, you will need to find 2 screws near the flywheel. By turning them, the flywheel will move away from the coil;
3. Moving the element a little, you need to install a template between it and the coil. After this, you will need to start turning the screws in the opposite direction until the flywheel comes close to the magneto. Then you need to remove the template and assemble the chainsaw.

Distinctive features

In our store you can buy a STIHL chainsaw at a price that is quite affordable for people involved in professional wood processing. The presence of factors such as:

makes the Stihl chainsaw the leader of this class of hand tools. You will never regret that you decided to buy a Shtil MS 661 chainsaw, since it is truly a very convenient and reliable mechanism for sawing and felling wood.

We have the best tool

If you need a Stihl chainsaw, the price of which is the best on the market, then you can purchase it in our company’s store. We offer our customers only the best certified tools from the manufacturer. Our price for the Stihl MS 661 chainsaw includes the manufacturer’s guaranteed obligations for the trouble-free operation of this machine. Therefore, if you need to buy a Stil chainsaw at a price that is quite reasonable, call the contact number or leave a request on the website.

Maximum number of revolutions

To limit this indicator, you need to use a screw marked H. To increase the number of revolutions, turn it clockwise, and to reduce them in the opposite direction. The maximum frequency should not exceed 15000 rpm.

If you make this figure larger, the device’s engine will wear out, which will lead to problems in the ignition system. When rotating this screw, you need to take into account the ignition processes of the device. If the slightest malfunctions appear, then the maximum speed value must be reduced.