Adjusting The Carburetor Of The Oleo Mak 937 Chainsaw

Adjustment tools

To tune the carburetor, you will need a Phillips or slotted screwdriver of different lengths or thicknesses, the size depending on the design of this unit and the features of the engine assembly. It should be noted that some manufacturers make Carburetors designed to use special tools.

In particular, special types of screwdrivers may be required to tune Husqvarna carburettors worthy of imported tools. It is advisable to clarify this question even when buying a chainsaw, so that you can purchase the necessary additional equipment in advance.

In addition, you will need refined gasoline or acetone to flush and clean the device. They are used to clean the outer surfaces of the carburetor. All internal channels are washed with kerosene, diesel fuel or white spirit. Before flushing, the carburetor is disassembled, all rubber or plastic parts that may suffer from contact with aggressive chemical compounds are removed.

Open-end or spanner wrenches are used to disassemble the carburetor. The internal channels are flushed in specially designated trays, sometimes plastic syringes are used for this.

How to properly adjust the carburetor on a chainsaw with your own hands?

A chainsaw is a useful, and sometimes simply necessary tool for the owner of a private house. It has a high degree of autonomy, can be used in the field, where there is no possibility of connecting to the power supply network. For some craftsmen, the chainsaw is one of the main devices that perform large amounts of work almost daily. Such loads knock down the factory settings, which were installed for all fundamental engine components.

The operating mode most often changes in the carburetor, which has to be adjusted again. Without understanding the design and principle of operation of this element, it is impossible to properly adjust it. The question concerns many users who closely operate chainsaws, so it will be useful to consider it more carefully.

When is carburetor adjustment necessary?

Initially, from the moment the instrument was sold, all Carburettors were adjusted and tuned at the factory. However, in the process of operation, the settings gradually go astray, and the operating mode changes in accordance with the operating conditions. Signs of a carburetor malfunction may include:

• Too high consumption of gasoline, thick smoke comes from the exhaust pipe;
• The engine power is clearly not enough to perform normal tasks;
• Engine speed “floats”;
• After starting, the motor stalls either immediately or after a few seconds
• The engine cannot be started at all;
• The chainsaw “shoots”, there are sharp claps in the tool engine.

It should be noted that during the running-in of a new engine, the carburetor is set to a reduced fuel supply in order to limit the engine power. After the end of the run-in, the fuel supply increases to the nominal value. These adjustments are made using the adjusting screws on the carburetor body (usually two or three).

Design and working principle

A carburetor is a device in which fuel (gasoline) and air are mixed in predetermined proportions, with the subsequent supply of the prepared mixture to the engine cylinder. Almost all models of chainsaws are equipped with Carburetors of the same type, so the device and principle of operation are the same.

The main structural elements of the carburetor are:

• The body is made of die-cast aluminum for light weight. Chainsaws constantly have to be moved from place to place, during operation they are held by hands, therefore, reducing the weight of the tool is the primary task of manufacturers;
• Diffuser with air damper, which are located at the inlet;
• Nozzles, which are valves for metering fuel;
• Sprayer that injects gasoline into the chamber (in the diagrams it is designated as the main jet)
• Fuel (Float) chamber.

Figure 1. Diagram of a chainsaw carburetor

The principle of the carburetor can be described as a cycle consisting of the following steps:

• Air damper opens during engine start.
• The piston stroke creates vacuum in the air channel, as a result of which air enters the diffuser, the amount of which is regulated by the position of the air damper.
• Gasoline flows from the gas tank to the float (fuel) chamber. The rate of its admission is regulated by jets.
• Gasoline and air are mixed in the diffuser, resulting in the formation of a fuel-air mixture, which then enters the engine cylinder. The more mixture enters the combustion chamber of the cylinder, the higher the power and speed on the engine shaft will be.

How to properly adjust the carburetor with your own hands?

After rinsing and completely cleaning the carburetor, assemble it and start adjusting. First of all, you should understand the purpose of the adjusting screws. The instruction will help with this, but some general points should be considered right away. The most common designations for screws are:

• H. adjusts the state of the main jet, i.e. Adjusts the maximum rotation speed of the motor shaft;
• L. adjusts the idle jets (responsible for the minimum shaft rotation speed)
• T. regulates the engine idling. It can also be designated LA or S, on some carburetor models it is not at all.

Turning screws H and L clockwise depletes the air-fuel mixture, and counterclockwise enriches it (the amount of gasoline increases). When the screw T rotates, the idling speed of the shaft changes. it increases clockwise, and decreases in the opposite direction.

Figure 2. Carburetor adjustment mechanisms

Before proceeding with direct actions, you should find and carefully study the information on the position of the adjusting screws (the magnitude of the angles of rotation during adjustment). This information is available in the instructions for the chainsaw. Then you need to prepare the workplace. lay the dust on a flat horizontal plane, direct the chain in the opposite direction from you. Detach all covers, remove foam rubber and air filter. At this preparatory operations are considered completed, you can proceed to the main part of the work.

Carburetor adjustment procedure:

• Smoothly tighten the screws H and L clockwise until they stop. Be careful not to break the screws. this will lead to the complete loss of the carburetor.
• Unscrew both screws one and a half turn.
• Run the engine for 10 minutes and warm it up. This is a necessary moment, since it will NOT be possible to correctly adjust the carburetor on a cold engine.
• Turning the screws H and L, alternately adjust the rotation of the shaft at maximum and minimum speed.
• Adjust the position of the screw T (or it may have another designation), the idle speed of the chainsaw is adjusted. It is necessary to achieve smooth and stable engine operation. Important Observe whether the chain is idling or not. If it moves, turn the screw a little more counterclockwise.

You can check the operation of the engine visually and by ear. Too rich mixture will cause thick smoke from the exhaust. When the lean mixture is being fed, a whistling sound is heard while the saw is running. Excessive economy mode is harmful. if the L screw is set to “lean” fuel, there will be problems with starting the engine. If the H screw is set to lean, the saw will noticeably lose power. You can determine the correct setting by the following criteria:

• At idle speed, the engine does NOT stall, and the chain is motionless;
• When the engine is running, there is excessive smoke from the exhaust pipe;
• The engine demonstrates good throttle response (picks up speed quickly when you press the accelerator).

A detailed description of the setting is available in the instructions that come with the instrument in the delivery set. It should be carefully studied as there may be some features or specific requirements set by the manufacturer and related only to this saw model. If all requirements are met exactly, the performance of the chainsaw will be restored to its original state.

How to customize China-made dust?

The design of the carburetor on Chinese chainsaws is not fundamentally different. The order and principle of adjustment also do not differ and are performed in the same order. The only difficulty that may arise during work is determining the purpose of the adjusting screws. Typically the T screw is at the top and the H and L are at the bottom of the carburetor body. One additional screw may be present.

Figure 3. Location of adjusting devices

Usually their purpose is determined empirically, slightly changing the position and follow the result. After the purpose of the elements is clearly defined, further adjustment is not difficult and is carried out in the usual way.

Chainsaw carburetor tuning is an important and necessary procedure that must be periodically performed to restore the normal operation of the tool. This process does NOT create fundamental complexity, but requires the user to be careful, attentive and follow safety rules. The chainsaw chain will usually NOT be removed as you will need to observe its position. Therefore, it is important to constantly remember about the possibility of launching it and take the necessary caution.

The adjustment should be done smoothly, with small changes in the position of the screws, so as not to cause too sharp changes in the shaft rotation mode. The result depends on the care and thoroughness of the user, and a properly tuned carburetor will extend the life of the tool.

Nuances of adjustment

When setting up carburetors for Oleo-Mac chainsaws, the following nuances usually arise:

• Mismatch of screw markings. Depending on the model, equipment vendor, or other factors, the markings may differ from those described. In such cases, it is recommended to carefully study the instructions supplied with the device.
• After adjustment, the chainsaw must be turned off and allowed to cool for 10-15 minutes to check its operation from a “cold” start.
• In the absence of experience or necessary knowledge, it is not recommended to adjust the screw “H”. This is due to the likelihood of setting up a poor-quality fuel-air mixture, which can become a prerequisite for wear of the piston group, failures in starting and engine operation.
• At all stages, it is required to control the engine speed using a tachometer. An oscilloscope or multimeter with this function can be a replacement for a tachometer.

Step adjustment

We will analyze an example of carburetor adjustment using the example of the Oleo Mak 937 chainsaw. The principle of adjusting the second dust is practically NOT different, therefore this method is applicable for the following models: 941c, 936. With other, less popular models (for example, Oleo Mak 362 or Oleo Mak 35), the similarity is NOT checked, but most likely serious differences comments.

Before setting up the Oleo-Mac chainsaw carburetor, a number of conditions must be met:

• Cleans air and fuel filters;
• Check the condition of the nozzles, make sure they are in good working order and clean;
• Assess the integrity of membranes: no damage, cracks;
• Check that there is sufficient fuel in the chamber.

Disassembly is NOT required for standard carburetor adjustment. There are screws on the outside that allow you to make all the necessary settings:

• L. low speed;
• H. high speed;
• S. idle.

Although the manufacturer recommends adjusting only the “S” screw, in practice this is not enough. Before adjusting, all three screws should be tightened all the way, and then unscrewed by 1.5-2 turns.

Adjustment is performed step by step as follows:

• The engine starts, warms up for 3-5 minutes at medium speed.
• Tachometer is connected.
• The work at low speed is adjusted using the screw “L”. It is necessary to achieve 1-1.5 thousand rpm. Engine without scrolling the chain, and when you press the accelerator. there is no failure of revolutions. If a failure is detected, the screw should be unscrewed until this effect is completely eliminated.
• High engine speed is adjusted with screw “H”. When the accelerator is pressed to the maximum, they monitor the increase in revolutions, it is important that they DO NOT exceed the maximum allowable value. It is recommended to set it 5-10% lower than the maximum speed, so as not to provoke increased wear of the internal combustion engine.
• The carburetor is fine-tuned with screw “S”. When the chain is moving at idle speed, the screw should be turned counterclockwise until it stops. If the internal combustion engine stalls, then the screw is unscrewed clockwise until stable operation is obtained.
• After the tuning procedures, the chainsaw is tested in real working conditions. Perform the setting again if necessary.

Oleo-Mac chainsaw carburetor. adjustment, repair

The stability and reliability of the engine of the Oleo-Mac chainsaw depends on the quality of the preparation of the air-gasoline mixture in the carburetor, it performs important functions. it allows you to smoothly change the engine speed, control idle speed. With prolonged operation, it may be necessary to reconfigure it. how to do it correctly and will not make mistakes?

Adjustment of carburetors on chainsaws Oleo Mak 941s, 936

Differences in adjusting comments. Oleo Mak 937, 941c and 936 chainsaw carburetor models are the same. We examined in detail the step-by-step adjustment, using the example of the 937 model, so any of the listed dust is regulated with the same approach.

Carburetor repair kit

To repair the carburetor, you will need a repair kit, the composition of which is as follows:

• Rubberized seals;
• Diaphragms: for pump and control;
• Needle valve assembly.

Oleo Mak chainsaw carburetor repair

If you cannot adjust the carburetor of the Oleo Allan chainsaw, then it probably needs repair. This can be determined by the following symptoms:

• The engine spontaneously and abruptly changes speed, stalls, and does not start;
• Increased consumption of gasoline;
• The presence of vibrations or increased noise during operation;
• Dark colored exhaust fumes.

Malfunctions and methods of their elimination

Common faults can be:

• Clogged filters or nozzles, removed by cleaning;
• Damage to the membrane (acts as a pump), is solved by replacement;
• Failure of the sealing gaskets, it is necessary to replace them with new ones after disassembling the body parts of the carburetor;
• A jammed valve (a needle that blocks the fuel supply to the carburetor), an assessment of its condition is required to determine the possibility of its further operation or replacement;
• Loose contact of the choke lever with the accelerator, restoration, repair or replacement of the unit is required.

Often, some of these problems occur after a long period of inactivity of the chainsaw. To restore operability, it is required to perform full maintenance of nodes and pre-start work.

Carburetor adjustment

When buying a chainsaw, the carburetor has factory settings and is adjusted to optimal operating modes. However, during operation, the engine (ICE), fuel pump, and carburetor wear out, as a result of which their repair, maintenance and adjustment are required. In this case, the role of the carburetor is to limit the minimum and maximum revolutions of the internal combustion engine.

The main criteria for determining the need for tuning the carburetor:

• The engine does NOT start, stalls, and does not react to pressing the accelerator;
• No idling;
• Increased fuel consumption, GIS does not develop power;
• Wear of the piston group, carbon deposits on the spark plugs, Black exhaust gases, incomplete combustion of gasoline.

The reasons for the failure of carburetor settings are as follows:

• Violation of the screws that regulate the minimum and maximum engine speed due to strong vibrations or mechanical stress;
• When the piston GIS system is worn out;
• Clogged air or fuel filters, nozzles, fuel line, breakdown of the intake valve.

What Carburetors Are Used

Oleo-Mac chainsaws are equipped with Walbro gasoline diaphragm carburetors for two-stroke engines. They are distinguished by their simple design, maintainability, and unpretentious operation. Walbro is part of the Stihl group of companies, therefore it manufactures products that meet international quality standards.

Is it worth doing DIY repair

Self-repair of the Oleo Mak chainsaw carburetor is advisable in the following cases:

• The breakdown is simple, obvious, the necessary parts are in stock;
• There is experience in performing such work, qualifications;
• The manufacturer’s warranty is NOT lost;
• There is no way to contact the service center or it is financially unprofitable.

Adjustment of carburetors on chainsaws Oleo Mak 941s, 936

Differences in adjusting comments. Oleo Mak 937, 941c and 936 chainsaw carburetor models are the same. We examined in detail the step-by-step adjustment, using the example of the 937 model, so any of the listed dust is regulated with the same approach.

Oleo-Mak chainsaw carburetor adjustment

To adjust the standard carburetor of the Oleo-Mac branded chainsaw, 3 metal screws are provided in its factory device:

• Screw L. is responsible for adjusting the engine at low starting speeds;
• Screw H. needed to adjust the maximum speed of the built-in motor;
• Screw T. allows you to set the number of revolutions of the internal combustion engine when idling.

Setting up the carburetor of the Oleo-Mak chainsaw is performed in the following sequence:

• First, on an instrument with a muffled engine, you need to set the factory settings of the built-in carburetor. To do this, they must be returned as indicated in the instructions;
• Next, you need to start the engine, wait for it to warm up and adjust the operation of the internal combustion engine at low speeds. To do this, the standard screw L must be slowly turned clockwise until the engine starts to work stably and evenly;
• If after that the chain on the bus rotates continuously, then the screw T will need to be turned in different directions until the headset stops;
• Next, you will need to connect a manual tachometer to the dust and return the screw H in such a way that the indicators of the device and the instructions in the instructions completely coincide.

To check the operation of the engine, you need to start the chainsaw and pull the gas trigger several times. If, at the same time, the internal combustion engine is rapidly gaining momentum, and not emitting extraneous sounds, then the adjustment of the unit was completed successfully.

The Oleo-Mac 941C chainsaw is equipped with an advanced ignition system consisting of a magnet controlled by an electronic control unit. When starting the engine, this system Reduces operator hand resistance, making the saw return smoother and safer.

Body Saws The Oleo-Mac 941 chain saws consist of a solid steel bar and a reinforced forged chain, lubricated by a fixed pump. The chain brake is a modified mechanism, which is activated by the direct assistance of a separate plastic lever.

Key features of this homemade hobbyist chainsaw include:

• Engine power. 2.5 liters. From.;
• Fuel tank / oil tank capacity. 320/220 ml
• Recommended length of brand tires. 40 cm;
• Weight. 4.6 kg.

Oleo-Mac chainsaw carburetor. adjustment, repair

The stability and reliability of the engine of the Oleo-Mac chainsaw depends on the quality of the preparation of the air-gasoline mixture in the carburetor, it performs important functions. it allows you to smoothly change the engine speed, control idle speed. With prolonged operation, it may be necessary to reconfigure it. how to do it correctly and will not make mistakes?

Oleo-Mac chainsaw carburetor adjustment

There are 3 metal screws on the factory unit for tuning a standard Oleo-Mac carburetor:

• Screw L. is responsible for regulating the operation of the engine at low speeds;
• Screw H. required to adjust the maximum speed of the built-in motor;
• Screw T. allows you to set the engine speed at idle.

The Oleo-Mac chainsaw carburetor is installed in the following order:

To check the engine, you need to start the chainsaw and pull the trigger several times. If at the same time the internal combustion engine rotates quickly and does not produce extraneous sounds, the device setup was successful.

Oleo-Mac 937 Chainsaw. Model Features

By developing this household model, the manufacturer was able to combine the high performance of a powerful professional saw and the low consumption of a budget amateur tool. The saw has high performance, compactness, simple and convenient design, which allows the operator to maintain and repair it on his own.

The Oleo-Mac 937 chainsaw is equipped with a robust chrome-plated cylindrical engine with a volume of 35.2 cm 3. To start the engine, the model is equipped with a manual starter, made according to the standard scheme. The continuous connection of the combustion engine and the saw body is ensured by the operation of the clutch system, all parts of which are made of metals that are resistant to heat and friction.

The options for this hobbyist chainsaw include:

• The volume of the factory engine is 2.2 liters. From.;
• Fuel oil / chain tank capacity. 400/220 ml
• The recommended tire length for the hinged tire is 35 cm;
• Weight. 4.4 kg.

The Oleo-Mac 937 chain saw for hobbyists is equipped with a durable muffler with free access to the internal elements, which allows you to freely inspect and clean the element at home.

Adjustment of carburetors on chainsaws Oleo Mak 362 and 35

These models are very old and today there is practically no information on their adjustment. But, since K. They use modern membrane-type carburetors, then the principle of adjustment should be identical to those discussed in this article.

The carburetor of the Oleo-Mac chainsaws is adjusted without disassembly using the adjusting screws. It is important to follow the sequence of actions, Watch for changes in engine operation, strictly follow safety rules during work and the result will be positive.

Italian chainsaw Oleo Mak 936 for household needs

The Italian-made Oleo Mak 936 chainsaw has excellent technical characteristics. During the assembly of such a tool, only high quality materials and advanced technologies were used, which makes it possible to use the chainsaw for many years. The saw can be used both for delimbing and for sawing and felling trees. It is the perfect tool for harvesting firewood.