Makita dcs 34 chain saw carburetor adjustment
Oleo-Mac 937 chainsaw. Technical Specifications. Carburetor adjustment and chain selection
The chainsaw option method is quite simple and consists of the following steps:
- Adjusting the motor for a smooth run at low rpm.
- Setting the carburetor for proper fuel consistency at the highest speed.
- Narrow carburetor adjustment for idle speed.
- Checking the chainsaw in all modes.
Now let’s understand how to adjust the carburetor more carefully chainsaw carburetor. Virtually all carburetor models have three adjustment screws. Screw (T) is responsible for narrow standby setting. Screw (H) adjustment for highest speed. Screw (L) controls the consistency at low rpm. By tightening the screws (L) and (H), the fuel supply and mixture becomes weaker, respectively the speed increases.
When buying a chainsaw Oleo-Mac 936, in addition the client receives a standard kit, which comes with any saw.
It should be noted that with all of the above, the customer receives a warranty on the chainsaw for 3 years.
For clarity, the chainsaw carburetor settings can be seen in the example below. After reviewing it no questions on the adjustment should not appear even for beginners.
Purpose and use of a Makita dcs34 chainsaw
According to the manufacturer’s recommendations, the Makita DCS34 chainsaw should be used for simple tasks that occur in everyday life. It would be ideal for cutting fence posts. May come in handy for cutting tree limbs or preparing firewood for heating the sauna or kindling the brazier.
If the Japanese knew where their chainsaw is actually used, they would be shocked. You’ll find the Makita 34 at the sawmill, where it can be used by everyone it comes into contact with. It is interesting that the quality of fuel and lubricants, as well as the proportions of the fuel mixture under such conditions are not respected, or respected approximately. But even in such “barbaric” conditions the Makita is capable of lasting quite long.
Since the Makita DCS 34-35’s resource is not designed for such conditions, after some time it is bound to fall into repair. But this does not stop anyone, t. To the cost of the domestic model and the professional model has a significant difference and when self-repair is more profitable to use a domestic model.
We suggest you watch a video about chainsaw Makita, in which the seller talks about the benefits of this model DCS 34-35.
Features of tuning and adjustment
To find out how to adjust the carburetor on a chainsaw, you should learn to distinguish between three screws (some models have only one).
The L and H screws are similar only in appearance, in fact they are different
Each screw has its own letter designation:
- The “L” serves for the low rpm option;
- “H” is needed to adjust the upper rpm;
- “T” is needed to adjust the idle stroke (models with only one screw).
The factory setting is good, and the tuning screws are used to adjust the motor operation in specific situations (work related to different climatic criteria).
The diagram shows the outputs of the carburetor adjustment screws with the cap closed
To adjust the chainsaw use a special tool
Only L and H screws are used for adjustment. To increase the RPM, turn them clockwise. To lower it, counterclockwise. The sequence in which the screws are used: L. H. T.
If there are doubts about the adjustment, it is better to contact a specialist, because incorrect adjustment can put the engine out of operation.
The structure of the carburetor chainsaw
Before you start adjusting, you should know the structure and mechanism of the carburetor. This will help avoid many “complications”. So, first of all, let’s remember the mechanism of the gasoline engine. There is fuel in the cylinder, when burned it creates a small “explosion” which makes a huge pressure. This pressure pushes the piston, the piston, coming in motion, turns the crankshaft. Pressure energy is converted into torque, which drives the chain with the sprocket.
When the engine normally runs, it only burns about 10 milligrams of fuel per cycle. The fuel mixture is prepared and fed to the carburetor.
Thus, the purpose of the carburetor is to combine the fuel mixture with the air in the right proportions. If these proportions are disrupted, engine malfunctions. For example if not enough fuel is injected and a lot of air is sucked in, then this mixture is called “lean”. And on the contrary, if there is not enough air and a lot of fuel, then it is a super-saturated mixture. Both cause malfunctions in normal engine operation and need adjustment.
The carburetor consists of the following basic parts, and although the design may differ depending on the model, the structure and operation mechanism is approximately similar:
- The base of the carburetor is a tube, in its features resembling an aero tube, through which the air flow enters;. Across the tube there is an air damper, its position either increases the air flow or decreases it;
- the tube has a narrowing. diffuser, which increases the speed of the air flow just in the place where the fuel inlet is placed;
- The fuel itself enters the air duct from the atomizer, it enters into it through the nozzle from the float chamber (in the photo it is marked as a fuel needle);
- the float chamber itself serves as a typical reservoir which purpose is to ensure a constant level of fuel at the entrance of the air channel.
The mechanism of operation of the carburetor is as follows. In the air duct, a sharp flow of air flows, and its speed will also depend on the position of the flap. the float level provides the degree of fuel channel opening and depends on the position of the same air valve. The air flow, passing through the diffuser, picks up the incoming fuel, atomizes it. This is when the mixture appears, which is sucked through the intake pipe into the cylinder.
In the float chamber the pressure level is approximately equal to atmospheric pressure, but in the air duct it is rarefied. Thanks to the difference in pressure, the fuel is sucked through the nozzle into the air duct. The more the choke is open, the bigger the airflow and therefore the more fuel that comes in. fuel. engine speed rises.
This is how the carburetor works. There may be aspects in its structure, but knowing how a simple carburetor works, you can always realize and find the purpose of other parts.
Adjustment of the Ural
It is little different in that it should not be carried out at high speed, but make sure that the chain picks them up quickly, but smoothly, without moving on the bar.
In any case, you should take the adjustment particularly seriously, because if it’s not done properly, the saw won’t stay with you long. Take care of your own tools and if you are not sure of your own, ask an expert.
READ How to Set the Angle of Sharpening for Band Saw
No matter which one of them, even a strong friendship, asks for attention and care. Then your chainsaw will be your faithful assistant for years to come.
Buying a chainsaw HUS365, you must be prepared that after a month of its use you will not want to deal with one saw, not counting this brand. This is explained by its reliability, accessibility, and most importantly, ease of operation.
Adjusting the carburetors on Oleo-Mac 941c, 936 chainsaws
There is no difference in adjustment. Oleo Mak 937, 941c and nine hundred and 30 6 chainsaw carburetor models are the same. We have investigated in detail the step-by-step regulation using the example of the 937, so no matter which of the listed duster is regulated with a similar approach.
For clarity, chainsaw carburetor options can be viewed as follows. After reviewing the setup no questions should arise, even for beginners.
Repair kit for carburetor
To repair the carburetor for you will be useful repair kit, the composition of which is such:
Aspects of adjustment
When adjusting carburetors for Oleo-Mac chainsaws, the following aspects usually appear:
- Inconsistency of auger markings. Depending on the model, machine supplier, or other reasons, the markings may be different from those shown on the map. In such cases, it is advisable to study closely the annotations supplied with the unit.
- After the option is finished, turn the saw off and let it cool for 10-15 minutes to check its performance from a cool start.
- In the absence of experience or the necessary knowledge, it is not recommended to adjust the screw H. This is due to the likelihood of establishing a bad fuel-air consistency, which can lead to wear of the piston group, failures at startup and motor operation.
- On all the steps it is necessary to control the revolutions of the engine with the tachometer. An oscilloscope or multimeter with this function can be a substitute for a tachometer.
READ STIHL Mower carburetor adjustment
step by step adjustment
Let’s analyze an example of carburetor adjustment using an Oleo Mak 937 chainsaw as an example. The principle of adjusting the other dusters is actually similar, so this method is applicable to the following models: 941c, 936. With other, less popular models (for example, the Oleo Mak 32 or the Oleo Mak 35) the similarity is not checked. But there are probably no harsh differences.
Before adjusting the carburetor for the Oleo-Mac chainsaw, a number of criteria must be met:
- unstained air and fuel filters;
- Check the condition of the jets, make sure that they are serviceable and unstained;
- Evaluate the integrity of the diaphragms: no damage, no cracks;
- check if the chamber has enough fuel.
Disassembly is not required for standard carburetor adjustments. There are screws on the outside that allow you to make all the necessary adjustments:
Although the manufacturer advises only to adjust the S screw, in practice this is not enough. Before adjusting, all three screws should be tightened all the way in and then unscrewed by 1.5 to 2 turns.
- The engine starts up, warms up for 3-5 minutes at medium speed.
- tachometer connected.
- The operation at low speed is regulated with the L screw. It is necessary to reach 1-1,5 thous. rpm. the engine without reversing the chain and when pressing the gas pedal the revolutions do not drop. If a fault is found, the screw should be unscrewed until this effect is eliminated.
- the highest speed of the motor is adjusted with the H screw. When the gas pedal is pushed to the maximum, they keep the acceleration under control, it is fundamental that they do not exceed a very permissible value. It is recommended to set it to 5-10% below the highest speed so as not to provoke increased wear of the petrol engine.
- The carburetor is fine-tuned with the S screw. When the chain is idling, the screw should be turned counterclockwise as far as it will go. If the gasoline engine is stalling, the screw is unscrewed clockwise until you get a measured run.
- After the option procedures, the chainsaw is tested under real operating criteria. Make the options again if necessary.
READ No oil in chainsaw chain
Features of Makita carburetor settings
A Makita chainsaw carburetor works on the same principle as carburetors made by other manufacturers. This important part is responsible for mixing fuel and air. The Makita chain saw is adjusted so that it does not run into problems. This will help protect the motor of the equipment.
- eliminate the risk of the carburetor creating a “lean” mixture;
- minimize the risk of creating an oversaturated mixture, which negatively affects the engine, provoking rapid deterioration.
If you need a new carburetor on your Makita chainsaw (you’ll tune it based on the standard manual), choose one that is identical in structure to the original.
- The basis of the basics is the air passage tube, which is connected to the choke (in the middle). The location of this part affects the amount of air that reaches the engine when it is running.
- Diffuser. It is not difficult to identify it, with a close look at the components of the carburetor. This part looks like a narrow tube, whose main function is to regulate the rate of air flow.
- Channel that supplies fuel from the float chamber (connected to the nozzle).
- A separate design that stands out is the float chamber, which looks like a standard fuel tank.
Screws for adjustment
Adjustment of the carburetor of a Makita chainsaw is carried out with a set of adjusting screws, which are in the body of this design:
- The screw marked L corrects for low RPM;
- screw marked H, it is used to adjust high revolutions;
- T screw for adjusting carburetor idle speed.
- Let the engine warm up (let it run for 10 min).
- Checking the air filter and cleaning the part.
- Stop the chain by turning the screw marked T (turn until it stops).
A tachometer is used to diagnose carburetor problems.
Important! Masters are advised to listen to the sound made by the screws when turning. A “squealing” sound may indicate oversaturation of the mixture.
Instructions for use of a Makita DCS4610 chain saw
An invariable helper and adviser to the new chain saw owner is the Operator’s Manual, which details the following sections:
- Gasoline chainsaw assembly, step-by-step.
- Safety in operation and servicing.
- Tooling Techniques.
- Table of specifications.
- Getting your Makita chain saw ready for work.
- Troubleshooting Chart.
- Here is a summary of information from the chapters.
Preparing for work
The tool is put into operation as follows:
- the chain saw is assembled according to the manual;
- the headset is attached;
- the chain is tensioned;
- Prepare a 1/50 mixture of fuel and oil;
- fuel and oil are filled into the appropriate tanks;
- Makita chain saw starts up;
- checking the brake, adjusting the carburetor, oil flow to the chain, etc. д.
To prepare a high-quality fuel mixture, 20 ml is taken. Makita original Makita two-stroke engine oil of high quality and 1 liter of. gasoline with an octane rating of at least 92.
The following simple steps will keep your Makita chain saw in working order for a long time:
- Check the functionality of the brake system, headset, before use.
- Before starting work, adjust the idle speed, lubricant supply, etc. д.
- Fill the chainsaw with fuel in a timely manner.
- Check oil level in tank.
- Clean filters.
- After work perform complete cleaning of tools from dust and other contaminants.
- Sharpen the saw chain in a timely manner.
- Perform routine inspections and repairs in a timely manner.
- Use only genuine parts and consumables.
- Have major repairs performed at service centers.
Troubleshooting the Makita DCS4610 chain saw
Let’s list the main problems of the DCS4610 gasoline model:
- no fuel
- Problems with spark plugs;
- broken wire;
- carburetor needs adjustment;
- the filter is clogged;
- Starter does not work;
- No compression in the cylinder, etc. д.
We suggest studying the full instruction manual of the Makita DCS4610 chainsaw.
In some cases (e.g. rough engine running) the carburettor has to be readjusted. In order to adjust the carburetor it is necessary to:
- Turn the carburettor adjustment screw counterclockwise as far as it will go.
- Start the engine and let it warm up in high rpm.
- Turn the idle speed screw to stop the chain.
- Turn screw another half turn counterclockwise.
- Check that the engine revs up smoothly and lets go of the rpm just as smoothly.
If the carburetor malfunction cannot be corrected, contact the nearest service center.
Now consider the basic characteristics. The engine of the Makita DCS34 chainsaw is a two-stroke, membrane-type carburetor with a built-in fuel pump that runs on a pulse from the engine crankcase. This is the standard circuit that almost all modern gasoline-powered saws use.
The power of the engine is only 1.3 kW, but thanks to the high speed and torque, the chain saw is confidently cutting logs with a diameter of up to 40 cm. The second variant of this saw, labeled DCS4610, has a capacity of 1.7 kW. All other features, appearance and components of the DCS34 and DCS4610 are identical. Fuel tank 0.37 liters. Oil reservoir 0.25. One fill of chainsaw, under normal conditions and correct carburetor adjustment should be enough for half an hour of continuous work, the DCS4610 will run out of fuel a little faster, t. к. it has a larger volume.
How to properly adjust the carburetor with your own hands?
After flushing and complete cleaning of the carburetor make its assembly and proceed to the adjustment. First of all, it is necessary to understand the purpose of the adjustment screws. The manual helps, but some general points should be considered at once. The most common is the following designation of the screws:
- H. makes adjustments to the main jets, t.е. adjusts the maximum speed of the engine shaft;
- L. makes adjustment of no-load jets (responsible for the minimum speed of rotation of the shaft);
- T. adjusts the idling speed of the motor. It can also be designated with the letters LA or S, on some carburettor models it is absent at all.
Turning screws H and L clockwise depletes the fuel-air mix, and counterclockwise enriches it (the amount of gasoline increases). When you turn the T screw, it changes the idle speed of the shaft: clockwise, it increases, and in the opposite direction, it decreases.
Before you start, you need to find and carefully examine the information about the position of the adjusting screws (the value of the rotation angles when adjusting). This information is in the instruction manual of the chainsaw. Then get your saw ready for work by placing it on a flat, horizontal surface with the chain pointed in the opposite direction to your body. Disconnect all covers, remove the foam and the air filter. This concludes the preliminary work and allows you to get down to the essential work.
Screw the two bolts H and L clockwise as far as they will go. Act carefully so as not to break the screws. this will cause complete loss of the carburetor. Loosen both screws by a turn and a half. Run the engine for 10 minutes and warm it up. This is a necessary moment, since the cold engine will not be able to adjust the carburetor correctly. Turn two and three screws (H and L) alternately to set the shaft rotation to the maximum and minimum rpm. By adjusting the Tclip (or it may have another designation) you adjust the idle speed of the chain saw. It is necessary to achieve a smooth and stable operation of the engine
It is important to check whether the chain is idling or not. If it moves, turn counterclockwise a little more.
Check the engine operation visually and by ear. Over-enriched mixture causes thick smoke from the exhaust port. A whistling noise is heard when the saw is running with the lean mixture. Overly economical is bad. if you set the L-closing screw to “lean” fuel, you will have problems starting the engine. If the H screw is set to a lean mixture the saw will noticeably lose power. You can tell if the setting is correct by the following signs:
- the engine does not stall at idle and the chain is stationary;
- there is no excessive smoke coming from the exhaust pipe while the engine is running;
- the engine has good good good response (picks up quickly when you press the gas pedal).
A detailed description of the adjustment can be found in the instruction manual that comes with the tool. It should be read carefully, as there may be some peculiarities or specific requirements that are set by the manufacturer and apply only to this model of saw. If all the requirements are followed exactly, the chainsaw will be restored to its original condition.
The gasoline saw has a complex design. The engine, carburetor, clutch and starter all put a lot of strain on the engine and break down over time. But there are malfunctions that occur much more often than others, and we will talk about them further.
The Makita DCS34 35 does not start
This is one of the most frequent situations that happens, but not always due to malfunction.
If for some reason the Makita DCS34 35 chainsaw does not start, the first thing to start with is to check the presence of fuel in the tank, and make sure that the fuel filter is functioning properly. Next, you need to make sure that the algorithm for starting the chainsaw is followed.
If these points are met, but the chainsaw still does not show signs of life, you need to act according to the following algorithm:
- Unscrew the spark plug and check it for spark, to do this with the ignition on, place the plug in the cap of the high-voltage wire and put it to the cylinder, then pull the starter a few times.
- plug the hole in the plug with your finger and pull the starter a few times (the air should rush out of the engine under your finger making a characteristic noise), that’s how you can check the compression. If there is no compression, the saw won’t start and will need a complete overhaul.
- Using a hypodermic syringe (more convenient), pour about 5 ml of fuel directly into the spark plug hole and try to start the machine. If the chainsaw starts, the problem is in the carburetor or faulty crankshaft oil seals. They can trap a lot of air and for this reason the fuel pump will fail.
- If all the previous methods did not help to determine the problem, there is a possibility that the spark plug is flooded. To find out, do the following. Screw the spark plug back in and try to start the chainsaw, then unscrew it and inspect it. Wet spark plug and a large amount of fuel in the cylinder (turn the saw upside down to check the fuel in the cylinder) confirms overfilling.
The spark plug floods
This is one of the most widespread malfunctions, the causes of which can be several. First, it is a failure of the carburetor or its improper adjustment. To fix it, you need to adjust the fuel quality and quantity screws, which are available on the carburetor. On how to do this read here.
The second is the contamination of the air filter, as a result of which the engine does not have enough air and the plug floods. In such a situation, there is one nuance, at the first cold start, the saw should start and immediately stall and at further attempts to start it does not start. Also recommend reading the article which explains in detail why the spark plug is primed and what to do.
If you have no experience in diagnostics and repair of gasoline saws, it is not advisable to repair the Makita DCS 34 chainsaw yourself. к. You can aggravate the situation, which will increase the final cost of repair.
Change the sprocket
The most frequent mechanical defects in a Makita DCS34 chain saw are sprocket or guide bar critical deterioration. You can solve the problem by replacing the parts. The sprocket is easy to remove, t. к. it is fixed on the shaft with a washer and a stopper.
To remove it, unscrew the side cover and remove the tire and chain. Next, remove the stopper from the shaft, then the washer, and after that the sprocket connected to the clutch drum is removed.
The sprocket rotates on the shaft by means of a roller bearing, which should be lubricated with lithol before assembling the saw.
Assemble in the reverse order.
Adjusting the carburetor of a Makita DCS4610 chainsaw with your hands
Changing the carburetor settings may be necessary in the following situations:
- Unstable motor. The reason. depleted fuel mixture.
- Excessive gas mileage, black exhaust. The cause is that the fuel-air mixture is oversaturated and does not complete combustion.
Adjustment can also help if your chain saw does not start well or does not run stably at idle.
Before you start with an independent carburetor adjustment you should get acquainted with its structure, operating mechanism and necessary tool kit.
The structure and principle of operation of a Makita DCS4610 carburetor
The main task of the carburetor of a Makita chainsaw, as well as any other, is to mix the fuel liquid (in this case a mixture of gasoline and oil) with air in certain, necessary for effective ignition proportions. When these proportions are not respected, the engine does not run correctly or efficiently. And later such improper operation can lead to its failure.
Diagram and principle of operation of the carburetor of a Makita chainsaw
In general, the carburetor is a one-piece cast metal housing.
The air for further mixing with the combustible mixture enters through the air filter and enters the diffuser (8). This is a specific form of chamber with available constrictions, thanks to them the air flow rate increases. The result is a more rarefied air mass.
The diffuser has an air damper and a throttle valve (7,9). The air damper controls the volume of the incoming air mass. The throttle, which is connected to the engine speed control lever, controls the flow of fuel into the combustion chamber of the cylinders, thus controlling the power of the engine.
At certain points in the diffuser there are fuel channels (11,12). By this, a stream of air mass is sucked in by the fuel. The fuel system of the carburetor includes:
The fuel feed mechanism works by altering the pressure in the crankcase, which is caused by the reciprocating motion of the piston in the cylinder. The pulse chamber of the fuel pump has a connection with the internal volume of the engine crankcase by means of the pulse channel (1).
Overpressure or underpressure in the crankcase actuates the diaphragm (4) of the fuel pump. Thanks to this connection the fuel pump works synchronously with the engine and depends on its rpm. Fuel comes from the gas tank under the action of the pump membrane, through the inlet channel of the carburetor (2). Further passes through inlet valve (3) and outlet valve (5) of the pump.
The precleaning process is carried out through the filter screen (6) through channel (10), past the needle valve (14) into the chamber (16) where the pilot diaphragm (18) is located. The needle valve mechanism (14) is connected to the pilot diaphragm (18) via the lever (17). The space below the diaphragm is connected to the outside air atmosphere through the channel (19).
In general, the Makita DCS4610 chainsaw carburetor operates by varying the pressure in the engine crankcase.
At the moment of suction a vacuum is created in the diffuser (8) and the air rushes in. The strength of the flow depends on the power (rpm) of the engine at that moment and on the position of the throttle valve (9). Also under the action of air rarefaction, fuel flows through nozzles (11,12) from the chamber (16). This mixes the fuel/air mixture and forms an air/fuel mixture which enters the cylinder and is combusted.
At the stage of fuel intake and combustion, as the space below the control diaphragm is connected to the outside atmosphere through the hole (19), the diaphragm (18) moves upwards. At this point it actuates the lever (17) which pulls the valve needle (14). The valve opens and a new batch of fuel mixture enters the chamber (16). When the chamber is filled to a certain level the control diaphragm moves back to the initial state and the valve closes. This regulates and maintains the fuel supply.
The volume of fuel entering the nozzle is controlled by the main screw (13) and the idle screw (15). The air-fuel mixture is enriched when the screws are turned out and becomes leaner when the screws are turned in. There is also an additional option to adjust the idle speed with another screw. When screwing it in, it rests against the lever, which is attached to the throttle axle. These three screws allow you to adjust the carburetor for more efficient operation of the Makita DCS4610 chainsaw in various conditions.
Adjusting the carburetor of a Makita DCS4610 chainsaw with your own hands
You may need to change carburetor settings in the following situations:
- Unstable engine performance. The cause is a depleted fuel mixture.
- Excessive fuel consumption, black exhaust. The cause is that the fuel-air mixture is oversaturated and does not complete combustion.
It may also help if your chain saw does not start right away or does not idle consistently.
Before you start to adjust the carburetor should be familiar with its structure, mechanism, and the necessary set of tools.
Design and operating principle of the Makita DCS4610 carburetor
The main task of a Makita chain saw carburetor, like any other, is to mix the fuel liquid (in this case a mixture of gasoline and oil) with the air in certain proportions necessary for efficient ignition. When these proportions are not maintained, the engine does not run correctly or efficiently. And later, such improper operation can lead to its failure.
Diagram and principle of operation of a Makita chainsaw carburetor
In general the carburetor is a one-piece cast metal housing.
The air for further mixing with the fuel mixture enters through the air filter and enters the diffuser (8). It is a specific shape of the chamber with available constrictions, thanks to them the airflow rate increases. The result is a more rarefied air mass.
The diffuser contains air and throttle valves (7,9). An air damper regulates the volume of incoming air mass. The throttle valve, which is connected to the engine speed control lever, controls the flow of fuel into the combustion chamber of the cylinders and thus regulates the power developed by the engine.
There are fuel ducts (11,12) at specific points in the diffuser. By it, a stream of air masses sucks in the fuel. The fuel system of the carburetor includes:
the fuel feed mechanism works due to a change in pressure in the crankcase, which is caused by the reciprocating motion of the piston in the cylinder. The impulse chamber of the fuel pump has a connection with the internal volume of the crankcase through an impulse line (1).
The increased or discharged pressure in the crankcase actuates the diaphragm (4) of the fuel pump. Due to this connection the fuel pump works synchronously with the engine and depends on its rpm. Fuel comes in from the petrol tank by the pump membrane, through the carburettor inlet (2). It goes through the inlet valve (3) and outlet valve (5) of the pump.
It is pre-cleaned through the filter screen (6) through channel (10) passing the needle valve (14) into the chamber (16) where the control diaphragm (18) is located. The needle valve mechanism (14) through the lever (17) connects with the pilot diaphragm (18). The space below the diaphragm is connected to the outside air through a channel (19).
In general, the Makita DCS4610 chainsaw carburetor is operated by the alternating pressure in the engine crankcase.
At the moment of intake, there is a negative pressure in the diffuser (8) and the air rushes in. the strength of the flow depends on the power (rpm) of the engine at that moment and the position of the throttle valve (9). Also under the action of rarefaction of air, fuel comes through nozzles (11,12) from the chamber (16). This mixes the fuel/air mixture and forms an air/fuel mixture which enters the cylinder and is combusted.
During the intake and combustion phase, as the space below the pilot diaphragm is connected to the outside atmosphere through port (19), the diaphragm (18) moves upwards. At this point it actuates the lever (17), which pulls the valve needle (14). The valve opens and a new batch of fuel mixture enters the chamber (16). When the chamber is filled to a certain level, the control diaphragm moves to its initial state and the valve closes. This regulates and maintains the fuel supply.
The volume of fuel entering the diffuser is controlled by the main screw (13) and the idle screw (15). When the screws are unscrewed the fuel-air mix is enriched and vice versa when the screws are screwed in the mixture is depleted. There is also an additional opportunity to adjust the idle speed with another screw. When screwing it in, it rests against a lever that is attached to the throttle axle. These three screws allow the carburetor to be adjusted for more efficient operation of the Makita DCS4610 chainsaw in various conditions.
Makita Dcs 34 Gasoline Saw Carburetor Adjustment
Adjusting the carburetor on a chainsaw with your hands
Adjusting the carburetor on a chainsaw allows the tool to operate efficiently at full power while consuming less fuel. Adjustment should be performed with a clean fuel filter and air filter. For more carburetors adjustment is done with 3 screws: high and low speed and idle speed adjustment.
The H and L screws are used to adjust the gasoline/air mixture ratio as determined by the choke opening on the carburettor. When you unscrew the screws, the mixture is enriched and rpm correspondingly goes down, when you tighten the screws, the mixture is depleted. rpm increases.
The designation H refers to the maximum rpm screw that controls the main nozzle, L. designation H refers to the low adjustment screw that controls the idle speed restrictor. The S screw is used to precisely adjust the idle speed. Sometimes, to simplify adjustment, the number of available adjustment screws of the carburetor is reduced.
Tuning the carburetor chain saw is divided into two stages. the basic (factory settings), carried out with the engine turned off. and final, performed on a running warm engine. Exact rotation angles are to be found in the instruction manuals for your particular chainsaw. the engine may be damaged if the manufacturer’s instructions are not followed.
Makita dcs 4610 chain saw does not start
Makita dcs 4610 chainsaw repair,repair.
The chainsaw is an indispensable tool both in the household and countryside. But even the most reliable “iron assistant” starts moping. he either doesn’t start or stops. There can be many reasons, both related to the quality of the fuel mixture and the engine.
There are a lot of nuances, we will not consider all of them in this article. And we “look closely” at that part of the engine, which is called the carburetor. And we will try to find an answer to the following questions: when it is necessary to adjust the carburetor of a chainsaw and, actually, what is the scheme of such an adjustment.
The structure of the carburetor of a chainsaw
Before proceeding to the adjustment, you need to know the structure and principle of the carburetor. This will help avoid many “complications”. So, to begin with, let’s remember the principle of the internal combustion engine. There’s fuel in the cylinder, and when it burns, it creates a little “explosion” that creates a lot of pressure. This pressure pushes the piston, the piston in motion rotates the crankshaft. Pressure energy is finally converted into rotational torque, which drives the chain via a sprocket.
During normal engine operation, it only burns up to 10 milligrams of fuel per cycle. The fuel mixture is prepared and fed to the carburetor.
Thus, the purpose of the carburetor is to mix the fuel mixture with the air in the necessary proportions. If these proportions are disrupted then the engine malfunctions. For example, when mixing, there is not enough fuel and a lot of air, then such mixture is called “poor”. And vice versa, if there is not enough air and a lot of fuel, then it is an oversaturated mixture. Both lead to malfunctioning of the engine and need to be adjusted.
The carburetor consists of the following basic elements, and although the design may differ from model to model, the arrangement and principle of operation are approximately the same:
- The basis of the carburetor is a tube, with its characteristics resembling a wind tunnel, the air flow enters through it;. Across the tube there is an air damper, its position either increases the air flow or decreases it;
- the tube has a narrowing. diffuser, which increases the speed of the air flow just in the place where the fuel inlet is located;
- The fuel itself enters the air duct from the atomizer, it enters it through the nozzle from the float chamber (in the photo it is marked as a fuel needle);
- the float chamber itself serves as a peculiar reservoir, the purpose of which is to ensure constant fuel level at the entrance to the air channel.
The principle of operation of the carburetor is as follows. Through the air duct a fast flow of air flows, its speed will also depend on the position of the choke. The level of the float provides the degree of opening of the fuel feed channel and depends on the position of the air valve. The air stream, passing through the diffuser, picks up the incoming fuel and atomizes it. At this point, the mixture is formed, which is sucked through the intake pipe into the cylinder.
the pressure in the float chamber is approximately equal to atmospheric pressure, but in the air duct is more rarefied. Due to the pressure difference, the fuel is sucked through the nozzle into the air channel. The more the choke is open, the greater the air flow, and therefore, the more fuel becomes. fuel. the engine speed increases.
This is the principle of carburetor operation. There may be nuances in its structure, but knowing how the simplest carburetor works, you can always understand and determine the purpose of other elements.
When adjustment is necessary
In general, the need to adjust the carburetor on STIHL chain saws and other brands comes up rather rarely. The signs of a disturbed carburetor are as follows:
- the engine starts and shuts down, or does not start. in this case the cause may be a “poor” fuel mixture;
- fuel consumption and exhaust emissions increase significantly (fuel does not burn completely). the cause may be an oversaturated mixture.
The adjustment itself is knocked down in very rare cases, namely:
- When the adjusting screws are loose, there are three screws in total. The reason can be vibration or the safety guard is damaged. This is quite rare if no one has touched the screws.
- In the case of significant engine wear, namely the piston. Then the factory settings are not suitable. In that case, the adjustment of the carburetor chain saw Patriot, or another model can save the situation for a while. But here we need to think more about engine repair, rather than deal with the adjustment of the carburetor of Husqvarna chain saw or something similar;
- the reason may be due to the formation of a clog in the carburetor, the cause may be poor quality gasoline, damage to the air filter or dross. In this option, in addition to adjustment, it is necessary to disassemble and flush the carburetor.
Adjusting the carburetor of a chainsaw
although quite rare, it may still be necessary to adjust the carburettor. It should be noted right away that not everything can be done by yourself, unless you have a tachometer and at least once to see for yourself how to do it correctly.
To adjust the carburetor of a Makita chainsaw, as well as most other models, three adjusting screws are designed. Although, some manufacturers have carefully removed two of them, leaving only one for user’s experiments. So, three screws, on the carburetor body they are marked with the following letters:
- L. with the help of this screw adjustment of low engine rpm is performed;
- H. High RPM adjustment;
- T. for adjustment of idling speed (it is left for experiments).
Generally the carburetors are already factory adjusted for optimum performance, and the screws are designed for more precise adjustment of the carburetor of Champion and other chainsaws, in difficult climatic conditions such as highlands, etc.п. Because the air is thinner there, the tool needs to be adjusted more accurately. Not necessary under normal conditions.