How to adjust idle speed on a chainsaw
The main stage
The engine turns on at medium speed and warms up for about 10 minutes. The idle speed screw must move clockwise. It is released only when the engine comes into stable operation. It is necessary to check that the chain does not move during this process.
In idle mode, the engine may stall (the reason is here). In this case, immediately turn the adjusting screw clockwise until it stops. Sometimes the chain starts to move. In this case, turn the adjusting screw in the opposite direction.
In order for the chainsaw to work properly, you need to carefully perform work on adjusting the carburetor in exact accordance with their sequence. If there are any irregularities in the operation of the device, it is necessary to completely disassemble it yourself. In most cases, it is necessary to replace any parts that have become unusable.
With a constant check of the quality of carburetor settings and the implementation of timely actions to improve its operation, problems with the chainsaw do not arise.
About which chainsaw to choose. read here.
The internal combustion engine of a chainsaw requires special attention due to the harsh operating conditions, and in particular this applies to the carburetor. Without periodic maintenance, no motor system will last long. Today we will talk about the process of adjustment and elimination of various malfunctions.
Final check at idle speed
Before this procedure, it is necessary to perform a full adjustment of the components of the carburetor when operating at maximum speed. Next, you should check the functioning of the device in idle cold mode. When the correct parameters are achieved during the adjustment, you will notice that the carburetor design exactly matches the following criteria:
- When the idle cold mode is connected, the chain does not move.
If violations are noticed in the above parameters or the device was not completely adjusted, you need to perform the main setup step again. Sometimes actions are performed incorrectly. In this case, the device may fail due to the loss of the correct node settings. In this case, you will have to contact a specialist.
How to properly adjust a Chinese saw. adjusting instructions
To correctly configure the carburetor of a Chinese chainsaw, you must first remember the factory settings of the device, then turn on the engine. Subsequently, you will have to leave it to work for several hours in order to accurately set your own parameters. Sometimes work is performed once after ten minutes of engine operation, however, many Chinese-made models require special handling.
- Activities start in idle mode. With the help of the adjusting screws, you need to achieve a systematic set of revolutions by the engine, so you should first let it run at low speeds. The deviation from the norm is the movement of the chain along the tire. In this case, you need to adjust the extreme screws to the optimal position so that the chain remains stationary.
- The transition to average speed turns is carried out. Sometimes the engine will smoke. This defect can be eliminated by tightening the screw to supply a leaner fuel mixture.
In this case, the smoke will disappear, but the engine speed will increase. It is necessary to adjust the settings until the level is reached when, when you press the throttle, the engine smoothly picks up speed, no sudden jerks or interruptions are heard.
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How to adjust idle speed on a chainsaw
Stable stable operation at any speed, developed power, efficiency, the use of technical capabilities in the amount provided and laid down by the manufacturer, and even the service life of a chainsaw. all this depends on its carburetor. In addition to the fact that this unit also needs to be kept in proper condition and serviced in a timely manner, it still needs to be properly adjusted. Setting up the carburetor of a chainsaw is not an easy task, but with a leisurely thoughtful approach and strict adherence to instructions, almost anyone can do it, and it should be carried out at the first sign of the need for this, and regardless of whether the new chainsaw is in operation or well-worn.
The following reasons, symptoms and malfunctions indicate the need to adjust the fuel supply unit (hereinafter referred to as the UPT, i.e. the carburetor):
- factory or custom settings were knocked down due to loosening of the adjusting bolts and vibration, or in the process of unsuccessful attempts to adjust the carburetor with a new one;
- the cover of the UPT case is damaged;
- the engine does not start or starts with an effort, and then stalls almost immediately;
- the saw does not work steadily at idle or does not hold them at all;
- excessive fuel consumption and too thick exhaust;
- spark plug electrodes are black (feeding a re-enriched mixture to the engine) or with a white coating (depleted);
- the chain saw does not develop maximum speed or power;
- the engine stalls during a set of revolutions;
- there is a strong vibration of the chainsaw;
- due to irregularities in the operation of the air-cleaning system, debris particles have entered the mechanism for distributing the air-fuel mixture;
- the piston group has significant wear. in this case, the DCC regulation is used as a temporary measure to make the operation of the tool more stable.
Naturally, when dirt gets into it, the fuel system must be flushed. adjusting the carburetor cannot solve this problem. A worn-out piston needs a major overhaul. However, in these cases, the setting is also performed.
It may also be necessary to adjust the DCS even when the brand or quality of fuel, atmospheric pressure, humidity and ambient temperature, altitude changes (when the place of operation changes from a plain to a mountainous area, then due to the rarefaction of air, and vice versa).
Before adjusting the DCF, it is imperative to make sure that both filters (air and fuel) are clean. In addition, there should be no air leakage into the motor from the side (through oil seals, a gasket under the UPT or its accelerating pump, or elsewhere), otherwise it will not be possible to adjust the carburetor.
Almost any DC drive is regulated by 3 screws:
- 1. The main jet bolt, designated “H” and used to set the saw motor to maximum speed.
- 2. Idle Jet Bolt, designated “L” and used for low speed setting. That is, to regulate idle speed.
- 3. Bolt of idle speed adjustment, designated differently by different manufacturers: “S”, “LA” (STIHL), “T” (Partner, Husqvarna).
There are also carburetors with fewer adjusting screws. This is how manufacturers protect their products from unprofessional interference and at the same time try to simplify their customization.
Before starting the adjustment, you should carefully study the operating instructions attached to the chainsaw, especially the part where the angles of rotation of the adjustment bolts are given. This is an important condition that will allow tuning without going beyond the operating parameters of the engine, correctly.
For safe regulation during its implementation, the following rules should be followed:
- 1. The tool must be stably placed on a flat surface of a rigidly fixed object (workbench, rack, table).
- 2. The chain should be directed away from yourself and others present.
- 3. Between the chain and any surrounding objects there must be a safe distance, which guarantees the impossibility of their mutual contact.
In such cases, you can adjust the carburetor on the chainsaw as follows. First, we launch the tool and warm it up for 10 minutes.
We begin adjusting the DCC by determining the position of the adjusting screw “L”, at which the idle speed will be the highest. To do this, very slowly and smoothly turn this bolt in one direction or the other. And so several times until the desired position is found. After that, we turn “L” by 1 / 8-1 / 4 turn (the required value is indicated in the technical documentation for the tool) counterclockwise (hereinafter PRCHS).
Then we continue to adjust the idle speed with the screw “S” (“LA”, “T”):
- If the chain is stationary after manipulating the bolt “L”, then it is necessary to smoothly rotate “S” (“LA”, “T”) clockwise (hereinafter POChS) until it starts to move. Then we twist “S” 1 / 8-1 / 4 turn back.
- If the chain moves, we rotate “S” (“LA”, “T”) PRCHS until it stops, and then we twist “S” 1 / 8-1 / 4 turn in the same direction.
The engine should run smoothly. And we check it, how it accelerates. It is considered that the motor in acceleration mode works normally if, when the accelerator is pressed smoothly, the revolutions in a short time and without “dips” increase to their maximum value. If the engine runs unevenly and / or accelerates poorly, then slightly. a maximum of 1/8 of a whole revolution. turn the “L” PRCHS. After that it is necessary to carry out the above setting “S” (“LA”, “T”) again. We repeat these adjustments until the motor runs evenly and accelerates well.
Now check the setting of the adjusting bolt “H”. To do this, we accelerate the engine to maximum speed. Only it is impossible to drive it for a long time without load, you need to pause. We look at the exhaust and listen to the operation of the engine. If too much gray smoke comes out of the muffler, and the chainsaw makes a lot of noise, then the carburetor is making an excessively rich mixture. In addition, the maximum speed of the power unit is lower than it should be. And also carbon deposits will form in it. In this case it is necessary to slightly tuck the POCH “H”. Then again we check the operation of the engine and, if necessary, repeat the adjustment.
When the chainsaw makes a squealing sound, the engine gets very hot, the exhaust is accompanied by a crackling and / or interruptions in ignition are heard, that is, there is a detonation. the mixture is too lean, and the maximum engine speed is higher than it should be. This leads to overheating of the power unit, piston burnout, rapid cylinder wear and spark plug burnout. In this case it is necessary to turn “H” by 1/4 turn of the PRCHS.
At the end of the adjustment, we check the saw at idle speed. With a properly adjusted DCT, it should work like this:
Chainsaw Attitude/Idle Adjustment
- 1. The chain is motionless.
- 2. The sound of the engine is almost like a four-stroke.
- 3. Pressing the accelerator leads to a quick set of maximum revs.
If these conditions are not fully met, use the “S” (“LA”, “T”), as indicated above, or repeat the setting from the very beginning.
This is a rough adjustment. For accurate, you need a tachometer. We do all the same, only we turn the adjusting bolts, focusing on the readings of this device. This will allow you to accurately and, most likely, the first time to adjust the carburetor, having achieved, depending on the model of the tool for working with a tree, the setting of idle speed at 2800-3300 rpm or higher and maximum. 11000-15000 rpm. Which ones should be set, you need to look in the technical documentation (operating instructions) for the saw.
After maintenance, such as disassembly and flushing, or previous unsuccessful attempts to tune, this assembly may become completely misaligned. So much so that the chain saw won’t start at all. In this case, it is necessary to configure the device of the engine power system in 2 stages, conventionally called:
- basic. with the engine off;
- final. produced on a warm engine.
At the first stage, the adjusting screws “L” and “H” are slowly screwed in the POCHS until it stops. In this case, you do not need to make great efforts and try to tighten them. Then we turn both screws back. for many models of saws by 1 revolution. And for some. by 1.5 turns. There may be other settings as well. This must be clarified in the technical documentation for the chainsaw. For a number of models, the tip is printed directly on the cover of their case near the adjusting screws.
This will accomplish the recommended factory default carburetor setting. In this case, do not touch the “S” (“LA”, “T”) screw, unless, of course, it has already been turned. When it is already twisted, you will have to work with it. Slowly screw in the “S” PRChS until it stops.
Let’s move on to the final stage. We are trying to start the engine. If there was no manipulation of the “S” (“LA”, “T”) adjustment and the “L” and “H” are set exactly as recommended, then it should start.
If “S” had to be tightened for the above reasons, then the engine, most likely, will not start right away. After each attempt, it will be necessary to tighten this screw by 1/4 of the POChS turn and try to start the engine again. In the end he must earn.
Then we warm up the engine for 10 minutes. If, after starting it or during warming up, the motor is unstable or the chain starts to move, then slowly and carefully rotate the “S” (“LA”, “T”) of the PRChS. As soon as the engine starts to work steadily and / or the chain stops, we immediately stop the adjustment. If the engine stalls, then turn this screw by 1 / 8-1 / 4 (see the technical documentation) of the POChS turnover.
In the process of warming up, the idle speed may begin to increase, then, again, it will be necessary to “S” (“LA”, “T”) start slowly turning the PRCHS until they become normal by ear. On an already warmed up engine, we continue to adjust the power system assembly, as described in the previous chapter.
After running-in on saws, only fine-tuning of the DCS is performed. To do this, you will definitely need a tachometer and technical documentation for the sawing tool used. The fact is that almost optimal settings have already been set at the manufacturer’s factory. Just for running in the engine and grinding in other moving parts of the chainsaw, the carburetor is set to prepare a slightly richer than the calculated optimal air-fuel mixture. Due to this, the maximum speed is slightly lower than the manufacturer’s design and, in addition, the motor is better lubricated. Thanks to this, the engine running-in and the running-in of the remaining moving parts are carried out in a gentle mode.
Therefore, if there is no tachometer and / or reliable information (passport data) about the maximum speed and at idle, then you should not change the factory settings after running in, since it will not work correctly. And in general, fine adjustment in this case is not necessary. the chainsaw will work fine with the existing basic settings. And if you really do it, then it’s better in a service center. It is recommended to entrust the jewelry tuning of the carburetor of a still completely new tool to specialists.
It is strongly recommended to mark the previous position of the adjusting bolts as accurately as possible before making fine adjustments on your own. This will allow, in case of an unsuccessful attempt, to return them to their place. to the basic factory settings. We start the regulation with the bolt “H”. After setting the maximum speed, we check the idle ones. If they differ from normal, set them first with “L” and then with “S” (“LA”, “T”). In doing so, we are guided by the rules and principles set out in the second chapter of this article. But we turn the adjusting bolts, focusing on the readings of the tachometer. Then we continue to tune the carburetor as described in the same chapter. We turn the screws, following the readings of the tachometer.
The carburetor of STIHL 180, 170 and other low-power chainsaws can be adjusted with only one screw. “LD”. They are set to idle speed.
The basic default setting is as follows:
- 1. Fully tighten the “LD” PRChS until it is firmly seated.
- 2. Then we turn it back POPS by 2 turns.
If you need to make additional or other adjustments, then first you need to warm up the engine for 10 minutes. Then if:
- idle speed is too low. turn “LD” POChS until the chain starts to move, after which we turn this bolt 1/2 turn back, PRChS;
- the tool chain moves at idle speed. slowly turn the “LD” PRCHS until it stops, after which we turn this bolt another 1/2 turn in the same direction.
And it is better to tune with a tachometer, not forgetting that the chain should not move at idle speed. The maximum idle speed of the STIHL 180 and 170 models is 13,500 rpm. Idle. 2800 rpm.
To adjust the carburetor of a STIHL chainsaw with a more powerful engine, proceed as described in the previous chapters. This also applies to the most popular models such as the STIHL 210, 230 and 250. For the basic setting (discussed in chapter 3) “L” and “H” are turned back 1 turn after screwing in. There are also carbureted saws that have a basic “H” setting of 3/4 of a turn. By the way, this information is indicated on the lid of the instrument body.
The angle (step) of rotation of the adjusting bolts during the adjustment of the DCS is 1/4 turn. Idle speed of the STIHL 210, 230 and 250 models. 2800 rpm, maximum no load. 13000 rpm.
For self-tuning the carburetor, you need to familiarize yourself with its device and remember the order of work that is carried out to adjust the parts responsible for the correct functioning of the constituent elements of the device and nearby parts. It is necessary to carefully handle objects for adjusting the chainsaw system, as well as to determine the correspondence of the set parameters to the maximum permissible values.
Dismantling the carburetor if it is necessary to check or repair components
The device of different models of carburetors is almost the same, so when working with them, you can use the standard scheme. All elements must be removed carefully, and then laid out in the order below, so that you can successfully place the items in place at the end of the repair work.
- The top cover is removed. To do this, unscrew the 3 bolts holding it in a circle.
- The foam is also removable, as it is the upper part of the filter that conducts air.
- The fuel hose is removed.
- The drive thrust is output directly to it.
- The cable end is detached.
- The petrol hose can be completely removed by systematically pulling it off the fitting.
To finally prepare the carburetor for overhaul or replacement of the smallest parts, you need to carefully disconnect it from the main system. Sometimes further disassembly is required. Unscrew the components carefully and fold the fasteners in groups, as these small parts are easily lost.
Do you need disassembly
You can adjust the carburetor of the chainsaw without any disassembly at all; in rare exceptions, you just have to remove the air filter cover. There is a considerable amount of contradiction here: on the one hand, the chainsaw is designed for unhindered access to the adjustment mechanism, on the other, it is recommended to use it as little as possible.
True, experienced fellers and sawers always carry a flat screwdriver with a long blade and periodically adjust the carburetor. The explanation is simple: when making a chainsaw, its carburetor goes through a rough adjustment, designed for a certain composition of air and fuel. It is clear that the conditions at the place of work are different from the bench.
When changing the brand of gasoline or, for example, increasing the humidity of the air, an experienced user of the chainsaw will always adjust the quality of the mixture for higher performance and less wear on the piston part. But this, we repeat, requires a lot of experience with a specific chainsaw and knowledge of the features of its behavior. In addition, the adjustment is incredibly fine. the screws are tightened by only 1/10. 1/20 turn.
Another reason for adjustment is the repair or replacement of the carburetor. In any case, adjusting the quality of the mixture should be carried out only if the serviceability of the carburetor is reliably known (there is no debris, the gaskets are not poisoned), the air filter is clean, the spark plug, the clutch and the ignition system are in perfect order. Otherwise, there is a high probability that the malfunction will be eliminated at one point and the adjustment will suddenly become incorrect, and the engine will start to work for wear.
How to set up a carburetor on a chainsaw?
Carburetor adjustment consists in adjusting the jet and air damper so as to obtain the optimal ratio of the amount of air and fuel in the fuel mixture.
If there is a lot of air in the fuel mixture and there is a lack of fuel, the mixture is lean, therefore the engine power is reduced.
If there is a lot of fuel and a lack of air. the mixture is oversaturated, incomplete combustion of the fuel occurs, which leads to smoke, soot on the piston and in the exhaust pipe and increased fuel consumption.
The device and principle of operation of the carburetor
The structure and principle of operation of the carburetor of a chainsaw are the same as those of carburetors of internal combustion engines and performs the same function: preparation and supply of a mixture of air with fuel to the combustion chamber of the engine.
The carburetor consists of the following parts:
- float chamber;
- needle valve;
- fuel jet;
- mixing chamber;
- throttle valve;
Atmospheric air, passing through the air filter, enters the air channel of the carburetor, where the diffuser is located, which reduces the diameter of the channel, as a result of which a reduced pressure is created behind the diffuser.
A throttle valve is installed behind the diffuser, which regulates the supply of air to the carburetor. By partially blocking or opening the air channel, the damper controls the air flow, thereby regulating the engine speed.
Under the influence of the reduced air pressure created behind the diffuser, gasoline from the float chamber is sucked into the mixing chamber through the fuel nozzle and the sprayer.
In the chamber, fuel is mixed with air, forming a fuel mixture, and then supplied to the combustion chamber. The throttle valve is mechanically connected to the fuel jet, which regulates the amount of fuel supplied to the atomizer. Consequently, it simultaneously regulates the supply of air and fuel to the combustion chamber.
The float regulates the fuel level in the float chamber, keeping it at the same level. It is connected to a needle valve that blocks the flow of fuel into the float chamber.
When the fuel level drops, the float will lower and move the needle valve, forcing it to tear off the fuel supply port. When fuel fills the chamber to a normal level, the float moves the needle to the closed position.
The engine speed depends on how much of the mixture of fuel and air enters the combustion chamber. The more we open the damper, the more revolutions.
There is an excess of air in the “lean” mixture, which is not good, as it has its drawbacks. Namely: insufficient energy in the flash (which means a loss of power as a result), excessive heating of the cylinder due to insufficient lubrication and high rpm, which leads to scuffing, and there it is not far to “jam” the engine.
How to adjust the carburetor on a chainsaw
The most common problem encountered in the operation of chainsaws is the improper operation of the carburetor, which leads to excessive consumption of fuel and a decrease in power, so any user should know how to adjust the carburetor on a chainsaw.
Chainsaw carburetors are arranged in the same way as car ones, and therefore everyone who is familiar with the principle of operation of an internal combustion engine is able to cope with adjusting the carburetor and can adjust it with his own hands.
New saws are supplied from the factory with an adjusted carburetor, but during operation the standard setting is violated and the saw needs to be re-adjusted. The documentation that came with your saw describes how to adjust the carburetor.
Carburetor adjustment is needed when the following symptoms appear:
- at idle speed, the saw operates at increased speeds;
- smokes a lot when working;
- does not start well both in a cold state and in a warm state;
- works at reduced revs and with reduced traction.
A “rich” mixture is a fuel mixture in which the amount of fuel supplied to the carburetor exceeds the norm. In this case, the fuel does not have time to burn completely and less energy is produced than with the optimal fuel-to-air ratio. Partially unused fuel gets into the muffler, then the chainsaw gives off a lot of smoke.
Adjusting the carburetor step by step
- We check the condition of the air filter. We remove it and either clean it or change it. If the air filter is clogged with dirt and sawdust, the chainsaw will not work normally.
- We check the condition of the muffler. It should be clean and unforgotten. Read more about cleaning the muffler HERE.
- Before you start adjusting the carburetor, you should fill the fuel tank at least half.
- If the chainsaw is capable of starting, then let it run for a few minutes so that it warms up. If the adjustment is carried out “cold”, then the mixture will be re-enriched after warming up.
- It is necessary to start the adjustment by adjusting the idle speed-screw L. It is highly desirable to have a tachometer, then focus on 2700 rpm. If not, then we need to find the highest idle rpm. In this case, the chain should not rotate. If it still turns (the chain, of course, not the Earth), then we achieve its stop by rotating the screw T. The sound of the chainsaw should be like listening to the file below. https://benzopilatut.ru/wp-content/uploads/2016/01/Chainsaw-idle.wav
- We regulate high rpm. screw H. If we rotate it clockwise, then the rpm will increase, and if counterclockwise, it will fall. We twist it until there are dips in the ignition. After that, we turn it out about one-fifth of a turn. The sound of the chainsaw when working at maximum speed should be the same as when listening to the file below. https://benzopilatut.ru/wp-content/uploads/2016/01/Chainsaw-maximum- revs.wav
- We check how the chainsaw is gaining momentum. She must type them smoothly and quickly. If the revolutions grow slowly, then slightly unscrew the screw L.
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Remember that the optimal carburetor setting is:
The internal combustion engine works by burning a premixed mixture of air, oil and gasoline. Chainsaw carburetor adjustment is needed to prepare the mixture in the required proportion. It depends on the operation of the carburetor whether the engine will operate at the declared power or stall.
How to find a malfunctioning carburetor
However, the adjustment may be preceded by the repair of the carburetor itself, when it cannot fulfill its function as a fuel mixer.
If fuel for some reason does not enter the engine, you need to check the condition of the fuel supply unit. Often the reason is the supply of low-quality gasoline, as a result, the fuel passages are clogged.
Correct Way To Adjust Or Tune The Carburetor On A Chainsaw
If the fuel mixture has stood for a long time, the additives have collapsed, the mixture can clog the passages and grate with sediment. In this case, a lengthy flushing is required, which is done with solvents in a service workshop.
Chainsaw RPM setting
For those who have a chainsaw, adjusting the carburetor with your own hands is not particularly difficult. To do this, you need to study the structure of the carburetor and remember the sequence of actions performed to regulate the elements, on which the correct operation of the parts of the carburetor itself and the elements located near it depends.
Before adjusting the chainsaw carburetor, you need to prepare the device. For this purpose, the following actions are performed:
- The motor is warmed up, for which it starts up about ten minutes before the start of repair work, and after they start it turns off.
- Air filter is being checked and rinsed.
- The chain is stopped by turning the screw T as far as it will go.
To ensure the safety of repair work, it is necessary to prepare a flat surface so that the tool can be placed neatly on it, and the chain can be turned in the opposite direction. A tachometer is required to determine abnormalities in the functioning of the carburetor.
Anyone who wants to know how to adjust the carburetor on a chainsaw should take into account that this procedure consists of two main stages. The first is carried out with the motor on, the second after the motor has warmed up.
For successful regulation of the carburetor, you should first study the instructions for using a specific model of a chainsaw to clarify additional nuances of adjusting this equipment.
At the first stage, the screws of low and high revolutions are turned clockwise until they stop, and then they are turned in the opposite direction by one and a half revolutions and kept in this position.
In the second stage, the motor is set to medium speed to warm up for ten minutes. The movement of the screw responsible for adjusting the idle speed should be done clockwise. It can be released only when the motor enters the stable operation mode. Make sure that the chain remains stationary during this process.
When the engine is idling, it can stall. In such a situation, immediately turn the screw clockwise until it stops. In some cases, chain displacement occurs. In such situations, turn the screw counterclockwise.
When deciding how to properly adjust the chainsaw. it is necessary to check the functioning of the motor during the execution of the maximum revolutions. With the correct functioning of the motor, after pressing the accelerator, the speed quickly increases to fifteen thousand revolutions per minute.
In the absence of such a reaction or an excessively slow increase in speed, it is necessary to turn counterclockwise the screw marked L. It is important to ensure moderation of movement, since the turn should not be more than one-eighth of a revolution of 360 degrees.
The maximum number of revolutions is limited using the adjusting screw marked with the letter H. To decrease the number of revolutions, turn it counterclockwise, and to increase it. in the opposite direction. The maximum frequency should not exceed fifteen thousand revolutions per minute. When turning this screw, take into account the ignition processes. If even subtle failures occur, the maximum number of revolutions must be reduced.
How to tune the carburetor on a chainsaw to function properly at idle speed? To do this, it is necessary to ensure that the following conditions are met:
- The chain remains stationary when idling.
- The sound emitted by the engine resembles the sound of a four-stroke unit.
- The motor increases revs at an accelerated pace, even with a slight push on the accelerator. With a smooth increase in pressure, the motor speed increases proportionally, reaching the maximum allowable level.
In case of non-compliance with these conditions, it is necessary to repeat the main stage of adjustment.
To correctly tune the carburetor of a Chinese chainsaw. you should remember its factory settings, and then turn on the motor. In order to accurately set your parameters, in the future you will have to keep it in working condition for several hours. In some cases, this problem can be solved immediately after ten minutes of engine operation, but many models of Chinese manufacturers need special treatment.
The setting is done in the following order:
- Regulation starts at idle speed. It is necessary to achieve a smooth increase in engine speed using the adjusting screws, so first leave it in a running state for some time at low speeds. The movement of the chain on the tire represents an abnormality. In this case, the optimal position should be achieved by adjusting using the outermost screws so that the chain does not move.
- The transition to average speed turns is made. In some cases, this is accompanied by smoke from the engine. This defect is eliminated by tightening the screw to bring in a less saturated fuel mixture. However, the speed of the engine speed will increase. It is necessary to change the settings until the motor starts to increase the speed smoothly when pressing the throttle, without interruptions or sudden jerks.
- The chainsaw motor is being checked. The tool is transferred to the minimum speed, after which the lever is quickly pressed and held at the maximum pressure for three seconds. If a malfunction occurs in the functioning of the motor, the screw should be gradually loosened until the optimal position is reached.
- The saw should have been operating under real conditions for some time. To do this, you need to saw the wood, and then inspect all the parts involved in this process. If there are deviations, it is necessary to correct them using adjusting devices. After eliminating all defects and setting the optimal settings for supplying the fuel mixture, the tuning procedure is completed.
Adjusting the chainsaw carburetor
Using a chainsaw greatly simplifies life even for amateurs, and in some professions it is almost irreplaceable. But, like any relatively complex equipment, the chainsaw needs regular maintenance. If it is performed out of time or poorly, then this leads to various malfunctions. One of the most common causes of problems is a wrong setting of the carburetor of the chain saw, knocking out due to movement of adjusting screws due to vibration or as a result of unsuccessful attempts to adjust.
Chainsaw adjustment is required in the following cases:
- the factory settings of the chainsaw carburetor are knocked down;
- the engine starts with an effort and stalls almost instantly;
- the ingress of debris particles into the fuel distribution mechanism due to a malfunction of the air purification system;
- the exhaust is too thick, the fuel consumption is too high, the fuel is not completely burned in the cylinder;
- significant wear of the piston group (in this case, adjusting the carburetor of the chainsaw is a temporary measure).
The carburetor is designed to prepare the fuel mixture for feeding into the engine. Violations of the proportions in the fuel mixture lead to malfunctions in the operation of the engine.
The design of carburetors varies from model to model, but they all operate on the same principle. The air stream moves quickly through the channel. The speed of its movement is regulated by means of a damper that closes the channel. The fuel supplied to the channel through the atomizer is mixed with air, after which the resulting air-fuel mixture enters the engine.
The carburetor always consists of the same set of parts, although it may vary slightly depending on the manufacturer. It includes the following parts:
- The foundation. It is a special tube that looks like an aerodynamic structure. A stream of air passes through it. In the middle of the tube in the transverse direction there is a flap, the position of which can be changed. The more it is pushed into the passage, the less air enters the motor.
- Diffuser. This is the constricted part of the pipe. With its help, an increase in the speed of movement of the air flow is provided precisely in the part from which the fuel is supplied.
- Float chamber. This element is similar in shape to a reservoir. It is used to continuously maintain the optimal fuel level in front of the entrance to the channel from which air is supplied.
- Fuel supply channels. The fuel mixture is in the float chamber, from where it enters the nozzle, and then is fed into the sprayer.
In order for the operation of the tool to be efficient and smooth, maximum output, and economical fuel consumption, timely adjustment of the chainsaw carburetor is required. Before performing it, you should check the cleanliness of the air and fuel filters. On most chainsaws, adjustments are made using three screws: high rpm, low rpm, idle.
Carburetor adjustment should be done with the utmost care, since errors are fraught with very significant consequences, up to engine failure.
Signs of a correct setting are as follows:
- the acceleration of the motor is carried out quickly and smoothly;
- the chain remains stationary at idle;
- the engine emits a smooth sound during operation, reminiscent of the sound of a four-stroke unit.
The carburetor of a Chinese chainsaw is adjusted in the same way as for models produced by European manufacturers, in fact, Chinese counterparts are copies of famous brand tools, but with some changes.
For this, the same screws H, L and T are used. The standard for the carburetors of Chinese chainsaws is the position of the screw L, at which it is loosened compared to the fully clamped state by one and a half turns. For screw H, the standard is one turn from the same position. Idle speed adjustment is performed on a warm engine.
On some models, only idle speed is regulated. However, the owners of Chinese chainsaws and service employees talk about the increased complexity of adjusting the carburetor for tools manufactured by Chinese manufacturers. Even for experienced craftsmen, it takes a little more time to adjust a Chinese chainsaw, unlike original tools.
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Do-it-yourself chainsaw carburetor adjustment
Chainsaw carburettor adjustment ensures that the tool operates efficiently at full power while conserving fuel consumption. Adjustments must be made with a clean fuel and air filter. For a larger number of carburetors, the adjustment is carried out with three screws: for maximum and minimum revolutions and idle speed adjustment.
The H and L screws adjust the ratio of the mixture of gasoline and air, which is determined by opening the throttle valve of the carburetor. When the screws are unscrewed, the mixture is enriched, and the revolutions accordingly fall, when the screws are tightened, the mixture becomes leaner. the revolutions grow.
The designation H refers to the maximum speed screw that controls the main jet, L. to the minimum speed screw that controls the idle jet. The S screw is used to fine-tune the idle speed. Sometimes, to simplify tuning, the number of available carburetor adjusting screws is reduced.
Chainsaw carburetor tuning is divided into two stages. basic (factory settings), carried out with the engine off. and the final, produced on a running warm engine. The exact value of the angles of rotation should be taken from the operating instructions for the specific chainsaw. Failure to follow the manufacturer’s instructions may result in engine damage.
The adjusting screws for maximum H and minimum L turns are slowly turned clockwise until they stop, then turned back 2 turns, other settings are also possible
We find the highest idle speed, for this we slowly turn the screw L in different directions. After finding the position of the highest engine speed, turn the screw L 1/4 turn counterclockwise. If the chain rotates at idle speed, screw T or (S) should be turned clockwise until it stops.
Checking and adjusting the maximum speed.
The maximum number of revolutions is changed by screw H. When screwing it in (clockwise rotation), the revolutions increase when it is turned out. decrease. Chainsaw engines have the highest rotation speed of 11500 rpm. up to 15,000 rpm. A higher speed does not provide ignition, moreover, it becomes dangerous for the engine. The rpm limit can be determined by the ignition interruptions. If they come, turn the screw H slightly counterclockwise.
If the engine is not checked for acceleration and maximum revolutions, then the adjustment of the chainsaw cannot be considered complete.
When the throttle trigger is smoothly pressed, the engine should confidently and quickly gain speed from idle to maximum (from 2800 rev. To 11500-15000 rev, depending on the unit). If revolutions are gained slowly, with a lag, screw L must be slowly unscrewed counterclockwise, but no more than 1/8 of a turn.
After adjusting the acceleration and maximum speed, the saw should be checked again at idle speed. the engine must run steadily and the chain must not move. Chainsaw tuning must be repeated if this condition is not met but with the exception of the basic adjustment step.