How to replace a primer on a chainsaw. Repair of the carburetor of the Chinese chainsaw

What is a primer in a chainsaw

Good afternoon, dear subscribers and guests of the channel! Thoughts to write an article on the topic of the primer arose at the moment when Husqvarna 240 came to my repair. Remember the article. “I can myself”. How some owners repair chainsaws.

In this article, I wrote as the owner of the saw independently changed the carburetor and at the same time primer. When I conducted an inspection of the chainsaws, I immediately noticed that the primer was not set correctly and it was precisely what I decided to tell you, maybe someone will be useful to someone.

How the carburetor of the chainsaws of a detailed description works

Many people know how the carburetor of a two.Stroke engine works on tools such as chainsaws, motorcycles and gas generators.

However, these knowledge is only generalized, and when there is a need to repair or regulate the carburetor, a bunch of questions immediately appear, the answers to which can be found yourself, if thoroughly, what is based on the principle of operation of the gas.Rosopila carburetor. This is what you have to figure out how the carburetor of the chainsaws of different brands works.

Why the gasopyle carburetor is called membrane

Before proceeding to consider the principle of operation of the carburetor of the chainsaw, you need to figure out why they are called membrane.

A membrane (membrane carburetor) is an improved model that is able to work in any position. This is very important, since the chainsaws, like the lawnmands, are operated in more than one position.

Therefore, membrane carburetors are capable of working in any position, which is their main difference from devices of an outdated structure or old.Style.

If a membrane is used in a new.Sample carburetor, then in old.Style models that are used on a chainsaw such as friendship, there is a float chamber.

It is in the float chamber that the appropriate volume is accumulated.

When the float drops down when gasoline is spent (the camera is devastated), then along with the float, the needle moves, which opens the fuel supply hole into the float chamber.

At the same time, the normal operation of the old.Style carburetor is ensured under one simple condition. It should be in the appropriate position.

When moving the device to the side is 90 degrees or more, the float will move, and therefore the needle will overlap holes for supplying fuel. That is why the old.Style chainsaws are intended only for operation in one position.

How to use a chainsaw

It is important to use a chainsaw correctly to avoid traumatic cases. The best about the rules of the chainsaw is said in the instructions for it. The main thing is to hold the tool tightly with two hands and all fingers.

How to start a chainsaw correctly

Before you start a motorcycle, you need to turn on the circuit brake and remove the tire protection.

  • Press the control button with a decompression valve, if any;
  • Activate the switching lever
  • Put the saw on the ground, pressing the rear handle with the right foot and with the left hand clasping the front handle;
  • Pull by the starter handle until the engine is launched;
  • Press the mode of switching the regime and put pressure on it before the work of the saw;
  • Increase the frequency of rotation of the idle speed and turn off the brake of the chain.

How to cut a chainsaw

To work correctly, you need to follow the main recommendations:

  • Keep the saw closer to the body. This will help maintain balance.
  • Legs wide up and bend the legs in the knees.
  • Keep your back straight.
  • Before switching to a new place, you need to turn off the engine by activating the brake.

Conditional will help to protect against random cuts. There should be a protective helmet with a mask on the head, dense gloves are needed for hands, a suit with lining, and for the legs. Durable shoes.

The chainsaws with a primer are a rubber transparent bubble, by definition they start faster and easier than the chainsaws without that pumping device.

But I will say this. In professional devices they often do not, and professional sawmills consider this part superfluous in the design of the chainsaw.

The launch of a chainsaw with a primer is carried out with its preliminary pumping in several presses, but if it is not, then the chainsaw is started without this procedure.

The launch of the cold chainsaw is carried out as follows:

Poulan Chainsaw Repair. How to Replace the Carburetor

Turn on the ignition, close the air damper, several energetic (not sharp!) pull the starter with movements, until the first outbreak appears, open the air damper and start a chainsaw, let it work for several minutes to warm up. Then proceed to work.

In addition to the fact that the primer is very controversial in the start of the chainsaw, for me there is generally or there is no difference in relief, so this elastic band still, maybe at the most inopportune moment it just won’t be used, so it will not be possible to use the chainsaw, so it is always with you need to carry this small condom to the primer, otherwise when you come to the cottage to file off the offshore, you can just roll gasoline on the trip and back to the store for this small elastic band, this is the same primer.

Apart from the listed nodes on the chainsaws, there is a system of cleaning the air supplied to the carburetor, a tire with a saw chain, a starter, a chain tension mechanism, ignition, a silencer, etc.

How the chain of the chainsaw works

Apart from the listed nodes on the chainsaws, there is a system of cleaning the air supplied to the carburetor, a tire with a saw chain, a starter, a chain tension mechanism, ignition, a silencer, etc.


The chainsaw engine has the highest revolutions about 13500 rpm. This imposes strict requirements for the oil added to the fuel mixture.

Clutch clutch

At low speeds, elements with friction pads (1), which have a degree of freedom in a circular direction, are attracted to the center of the shaft with springs (2) and do not transmit rotation to the drum (3) connected to the sprocket of the driving chain.

When the speed of the chainsaw motor achieves values ​​in which the centrifugal force exceeds the force of the springs, the friction segments are pressed to the inner surface of the drum and begin to twist it.

As a result, the leading star begins to spin, setting the saw chain.

As you can see in the photo, the asterisk is behind the clutch.

Other chainsaws, an asterisk can be on the outside of the clutch.

The main advantage of the couplings of this type will be that when jaming the circuit, the clutch of the chainsaw slopes, not the grinder of the engine and without causing a breakdown of devices that transmit movement from the motor to the circuit.

Ignition system

The electric ignition of the chainsaw contains a flywheel (1) with built.In magnets, the ignition module (2) with an electrical circuit, a candle (3) and a high.Voltage wire (4).

The spinning flywheel with magnets induces in the module E.D.With., transformed using an electronic signals supplied to the candle.

replace, primer, chainsaw, repair, carburetor

As a result, the spark is slipping between the contacts of the latter, which ignites the air-fuel mixture.


Below is a diagram of another carburetor of a chainsaw.

Carburetors have a throttle, which allows you to impoverish or enrich the mixture depending on the criterion of work.

For a narrow option, there are a certain number of screws with which the adjustment of low and large revolutions of the motor is made, as well as idle.

Air filter is installed on top of the carburetor, a cleansing air entering it.

Fuel system

So that as the fuel consistency is spent, the fuel tank was filled with air and negative pressure was not created in it, which would not allow the combustible to enter the carburetor, and with all this, so that a fuel does not flow out of the opening for air, in the lid that closes the pouring hole, Brown of a sapun. And by the way, if the saapun clogs with a dirty rod, then the chainsaw will staller.

From the tank, fuel sways through the hose freely dangling in the tank. Thanks to this, regardless of the position of the chainsaw, the hose is always immersed in fuel. The fuel filter is attached to the inlet end of the hose. A combustible carburetor snut.Fuel.

To facilitate launch, part of the chainsaws are equipped with a manual pumping pump. A primer.

When starting a chainsaw with a primer, the carburetor is filled with fuel in advance (an excess of fuel flows back into the tank). Thanks to this, the engine triggers, t.To.

The stage of filling the carburetor is already passed by fuel, which is made without a primer by a carburetor pump due to the starter.

Air purification system

Preparatory filters can have a different design and consist of several parts, namely, of the mesh (2) and snowy (1) filter (see. Photo below).

The latter prevents snow in the air treatment system and is used only in winter, at a plus temperature it is removed.

In certain models of chainsaws at the preparatory cleaning stage, air purification is used using centrifugal forces. The air flow is twisted by the impeller of the flywheel, as a result of which impurities are discarded from the absorbing pipe going to the filter of narrow cleaning.

Narrow cleaning filters are made of diffusion foam, nylon mesh and other materials.

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How to replace a primer correctly

Good afternoon, dear subscribers and guests of the channel!

Thoughts to write an article on the topic of the primer arose at the moment when Husqvarna 240 came to my repair. Remember the article. “I can myself”. How some owners repair chainsaws.

In this article, I wrote as the owner of the saw independently changed the carburetor and at the same time primer. When I conducted an inspection of the chainsaws, I immediately noticed that the primer was not set correctly and it was precisely what I decided to tell you, maybe someone will be useful to someone.


The starter mechanism consists of a drum (1) with a cable (2) and a handle (3), and from the frame (4) with a returning spring. With a sharp stretching of the handle up, the drum ratchet clicks with the teeth available on the shaft of the motor, and turns the crankshaft. When the handle is released, the returning spring returns it to the initial position.

To crank the crankshaft at the speed at which the engine is launched, a certain force is required. It is often not possible to start a chainsaw from the 1st jerk, you have to pull a couple of times. To facilitate the launch, different methods are used. The enrichment of the fuel consistency using a carburetor dash, or a decrease in pressure in the cylinder using a decompression valve (to facilitate the scrolling of the crankshaft). The valve is made automatically closing with increasing pressure in the cylinder that occurs during ignition of consistency. From time to time, an additional spring is used in the starter mechanism, which, when stretching, is initially compressed, and then sharply unleashed, unwinding the motor.

The main and more complex links of the chain are cutting links that are divided into right.Sided and left.Handed. The upper face of the tooth is the widest of all parts. It provides a wide cut, excluding the stuck of other links.

How to install it correctly

The design of the primer has two outputs for connecting hoses from the chainsaw. Precisely, one of them is the entrance, and the second exit. The entrance must be connected to the carburetor. Access to the opposite hose going to the tank.

At the time of pressing on the primer, fuel is squeezed out of it into the tank, then the valve at the output closes and due to the discharge in the primer, through the input pipe, fuel extends to the carburetor.

As a rule, the output pipe has a large length, the input smaller. Connection is better to start with the input pipe, this makes it possible to check the performance of the primer, at least I do just like that.

By connecting the primer to the input pipe going from the carburetor, you can put it on it several times, until gasoline starts to come from the output pipe. This is what suggests that the primer is set correctly.

The brake of the chain

Turning on the brake of the quapia can be contact and inertial. The 1st occurs when the brake stop is pressed (1) on the hand of a worker, which spontaneously occurs when a saw was discharged. The shift of the stop arising with all this leads to tightening the brake tape (2) on the drum of the clutch and its stop, as a result of which the saw chain stops.

The inertial inclusion of the brake is based on the inertial forces that occur during a sharp strike in the bus, which affects the brake elements, which leads to the same result as in the first case. Tightening the brake tape and stopping the chain. Inertial inclusion of the brake is more frozen than contact. But the 2nd more firmly. Any preparation for work, also assembly of the chainsaws after its repair or maintenance should end with checking the operation of the brake of the quapi. If it does not work, the saw should be considered faulty.

Design and operation of individual nodes

The individual components of the chainsaw considered above, in turn, consist of different parts. To independently repair the equipment, you need to know the design and operation of the main systems.

Ignition system

Firstly, the LEADING STILLING SYSTEM TYPE Contact type. Now it is practically not used. Modern manufacturers equip their equipment with electronic ignition (photos later disassembled). For this reason, there is no need to regularly clean the contacts and set the required distance between them.

The ignition system that causes a spark when starting the engine consists of the following parts:

The appearance of the elements of the ignition system of one of the models of the stihl chainsaw is shown in the following photo.

Magneto. This is an alternating current electric generator that supplies the voltage to the spark plug. It can be two types:

Schematically, ignition systems with contactless and contact types of magnets are presented below.

The magnet of any type includes the following parts:

Primer bulb not working on chainsaw

Part of the electronic unit usually includes diodes, resistors of various sizes, thyristors, capacitors. The connection diagram depends on the saw model.

Read Husqvarna chainsaw Sapun 137 Video

The ignition works according to the following principle:

  • Когда маховик вращается с прикрепленным к нему постоянным магнитом, в системе индуцируется электродвижущая сила;
  • The electronic unit converts the current generated in the circuit into electrical signals;
  • They are transferred to a candle;
  • A spark is formed between the contacts, which causes ignition of the fuel mixture.

Initially, the ignition is regulated in such a way that sparking occurs when the engine piston does not reach its upper dead point by about 3-4 mm. If you focus on the circle of the crankshaft, it corresponds to the angle of 28 degrees.

Thus, due to the presence of ignition, the fuel mixture is ignited, which ensures the transition of the engine to working condition. Periodically the system should be configured, which is easy to do on your own.


The carburetor is necessary for the continuous operation of the engine. It consists of the following structural elements:

  • Solid aluminum corps;
  • Nozzles that are valves that regulate the amount of fuel;
  • Diffuser;
  • Float chamber;
  • Spray.

The valve is installed in the carburetor housing, which regulates the supply of atmospheric air, pulse channel, diffuser, inlet fitting, two screws (idle and main). Very often, manufacturers of chainsaws supply their products with carburetors of frequently sold brands.

Most models of chainsaws are equipped with the same (in design) carburetors. Schematically their device is shown in the photo below. Only rare rare modifications made in China may differ in the absence of a number of details in the carburetor.

In order to correctly adjust the carburetor of the chainsaw, it is necessary to understand the principle of its work, namely:

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