How To Adjust The Carburetor On A Patriot Chainsaw

Cases in which to tackle the adjustment

It is not often necessary to adjust the carburetor in a chainsaw; problems of fuel intake or wear of individual components can be considered much more common. However, there are also cases in which it is precisely the adjustment of the mechanism that is needed. How to determine this? On the following grounds:

Immediately after starting work, the motor stops. It happens that it does not start working at all. The cause of this problem is an excess of air and a lack of fuel.

The fuel consumption has increased, as a result of which the exhaust gases are emitted in large quantities. Here the reverse process takes place. The mixture is oversaturated with fuel.

The adjustment can also be disturbed due to purely mechanical reasons:

  • Strong vibration can damage the protective cap. The result of this is that all three bolts are loose.
  • Worn piston part of the motor. In this situation, by adjusting the carburetor, only a temporary improvement in performance can be achieved, and the worn out unit must be replaced.
  • The carburetor can become clogged. Here the reason is low-quality fuel, scale or a damaged filter. In this case, the device requires complete disassembly, flushing and adjustment.

How the carburetor works in a chainsaw

Repair is not possible if you do not know how the repaired mechanism works. If you know the principle of operation and the components of the device, a breakdown will be detected much earlier.

How To Adjust The Carburetor On A Patriot Chainsaw

The carburetor is one of the most important parts of an engine. A fuel mixture is prepared and supplied in the carburetor, which includes fuel and air. If the ratio of air and fuel is violated, the engine’s performance deteriorates, and sometimes it can completely stall. To get the carburetor to work properly, you must know that it consists of:

A tube with a cross flap to regulate the air flow.

Diffuser. Constriction allowing to increase the air flow rate. Located next to the fuel inlet.

  • An atomizer that serves to supply fuel (indicated by a fuel needle in the diagram).
  • Float chamber, where the fuel level is adjusted at the inlet channel.
  • Diagram showing the process of interaction of fuel and air flow

Description of the principle of operation: with the help of an air jet, fuel is sprayed in the diffuser area, and a mixture is created that enters the cylinder cavity. With an increase in the amount of supplied fuel, the engine speed increases. Different carburetors work according to the same principle.

Step-by-step disassembly of the carburetor

The process of disassembling the carburetor plays an important role in how to adjust the carburetor on a chainsaw. Carburetors of different chainsaws do not fundamentally differ from each other, for this reason, consider disassembling the Partner chainsaw. All elements must be carefully removed and folded to facilitate the subsequent assembly process.

Removing the top cover is done by dismantling three bolts. After that, the foam rubber, a component in the air filter, is dismantled. The indicated bolts are marked in red in the figure.

After that, remove the fuel hose and drive rod. The upper indicator indicates the fuel supply hose, the lower indicator. The link in the drive

Now we move on to removing the cable end. The arrow points to the tip to be removed.

On the left side, we dismantle the gasoline hose.

We make the final disconnection of the carburetor, now it can be adjusted. The carburetor has a rather complex mechanism, for this reason, if there is a need for further disassembly, you need to carefully remove the elements, since they are small and easy to lose.

There are many small components in the carburetor, which are best placed in the correct order so as not to confuse anything.

How to adjust the carburetor on a chainsaw instruction

If you have enough experience and dexterity, you can adjust the carburetor in the chainsaw, which is a complicated procedure, one might say, jewelry. It is about how to adjust the carburetor on a chainsaw that will be discussed today.

Setting and adjusting

To adjust the carburetor of the chainsaw, you will have to use only three screws (some models are equipped with one screw at all). Cogs L and H are similar only in appearance, their functions are completely different

Each screw has its own letter designation:

  • “L”. To adjust low rpm;
  • “H”. To adjust the upper speed;
  • “T”. To adjust idle speed (models in which one screw has only this).

The factory adjustment is considered to be the most suitable, and the screws are used to adjust the operation of the motor for special situations (work, in difficult climatic conditions). The chainsaw is adjusted with a special tool

Adjustment is carried out using screws L and H. To increase the speed, they turn clockwise. And to reduce the speed. In the opposite direction. The screws are tightened in the following sequence: L. H. T. If you are not sure how to adjust the carburetor on a chainsaw, it is better to ask a professional for help, because if the setting is incorrect, the motor may break.

Ural chainsaw carburetor: device, adjustment, repair, revision

All Ural chainsaws were equipped with standard KMP-100 carburetors and its modifications with minor changes. And it was the only carburetor for chainsaws produced in the USSR. Later, with the advent of the newest and last in the USSR model Ural 2t Electron, the KMP-100U carburetor began to be used. And he was the only one for chainsaws produced in the USSR, which stood on Druzhba gasoline chain saws.

What other carburetors were put on the Ural 2t Electron chainsaw

On the Ural 2t Electron chainsaw, carburetors from other two-stroke engines with the following engine parameters were often installed, and are being installed today:

  • Power 5.5 hp.
  • Combustion chamber volume 90.4 cc,
  • Piston diameter 55 mm.

Sometimes carburetors were installed from much more powerful engines. For example, from motorcycles “Minsk”, “Voskhod”. True, there is a drawback, the supply of the fuel-air mixture significantly increases. It was lowered by adjusting the screws. The engine was running, but the fuel consumption was significant.

Device and principle of operation

The carburetor of the Ural KMP-100U chainsaw is of a membrane type. It does not have a float chamber and a floating float with a needle that cuts off the fuel flow as the chamber fills like older carburetors. This gives the advantage that the Ural 2t Electron chainsaw engine can work in any position, even upside down. The float carburetor cannot operate in an inverted position.

The system of the KMP-100U carburetor can be considered complex, because it must ensure the operation of the engine in three modes:

  1. Running.
  2. Idling.
  3. Maximum RPM.

For each mode, special channels for the supply of fuel, air and the position of the dampers.

The appearance of the new KMP-100U carburetor used on the Ural 2T Electron chainsaw

When starting a cold engine, the conditions for the formation of a working air-fuel mixture in the combustion chamber are very unfavorable for the following reasons:

  • Low crankshaft revolutions with a manual jerk of the starter, weak compression of the fuel mixture in the combustion chamber;
  • Some of the fuel is lost on the cylinder walls;
  • Low temperature makes ignition difficult.

Therefore, to facilitate starting, the supply of a rich mixture is required. gasoline, less air. The air supply flap from the air filter in the cold start mode is closed, and the gas supply is increased due to pumping (suction) with a primer.

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After starting the engine, a vacuum is created in the combustion chamber during the piston stroke, so the fuel mixture from the carburetor begins to be sucked in there. air is required for oxygen supply and complete fuel burnout. Air damper opens.

When the throttle is pressed, the throttle valve opens fully, gasoline and air flow in full flow, the engine runs at full speed.

The flow of gasoline at this moment is regulated only by the calibrated orifice of the jet in the carburetor.

Ural chainsaw carburetor repair kit

For carburetors KMP-100U, repair kits are still sold. A set of gaskets, a membrane, in other configurations there may be a rocker arm with a spring to it.

In the days of the USSR, when not only chainsaws were in short supply, but also spare parts for them, the gaskets were made themselves, from sheet paronite.

In the absence of paronite, the gaskets were made of thick single-layer paper (not cardboard) coated with oil paint.

How to adjust the carburetor on a Ural chainsaw

Adjustment of the KMP-100U is simple and accessible to every user. The carburetor has two adjusting screws (analogs of the H and L screws on some modern imported chainsaws) for adjusting the average and maximum speed. They are accessible from the outside, no need to disassemble the case for adjustment.

Above you can see 2 screws with springs, these are the adjusting screws

Adjustment of the carburetor of the Ural chainsaw is carried out on a warm engine. Initial tuning should be carried out on a warm, but muffled engine.

  1. Both screws can be screwed in all the way, but without excessive force. Screws have sharp, fine points that can deform if overtightened.
  2. Then the first screw, which is closer to the cylinder, is unscrewed by 1 turn. The second screw is unscrewed by 0.5 turns.
  3. They start the chainsaw, give full speed. In case of a drop in revolutions, the screws can be unscrewed by another 1/3 or 1/4 turn, listening to the engine’s operation and finding the optimal mode.

It is impossible to know the exact number of revolutions. On each chainsaw this is individual, depending on the characteristics of the carburetor, the state of the piston system, fuel quality, outside temperature, etc.

To adjust, it is enough to remove the cover, there is no need to remove the carburetor itself from the chainsaw

Lack of tightness

Other problems with the KMP-100U carburetor are loss of tightness. The gaskets between the carburetor and the engine body, and between the parts of the carburetor, must not suck in air during operation and leak fuel when the engine is turned off.

The gaskets can deteriorate for the same reasons as the membrane, that is, dry out, become fragile from time to time.

How to properly adjust the carburetor on a chainsaw?

Place the tool on a firm, level surface to set up the assembly. It is best to adjust the carburetor of the chainsaw in a place protected from dust and moisture.

The node setup process should look like this:

  1. First you need to unscrew the fastening bolts and remove the protective saw body. This will make it possible to inspect the carburetor and, if necessary, clean it;
  2. Next, you need to remove the standard air filter of the tool. If the saw is equipped with an additional foam insert, then it must also be removed;
  3. After that, you need a screwdriver, which you need to tighten the bolts marked H and L clockwise until they stop. This must be done very carefully so as not to break the bolts;
  4. Then both screws should be unscrewed 1.5 turns in the opposite direction;
  5. Next, you need to start the chainsaw engine and let it run for about 7 minutes;
  6. As soon as the engine cylinder heats up, you will need to start turning bolt L until the internal combustion engine starts working at maximum speed. Immediately thereafter, the bolt must be turned 1/4 turn in the opposite direction;
  7. Then you need to adjust the operation of the motor at high speeds. To do this, you need to connect an electronic tachometer to the engine, and start turning the bolt H until the readings on the instrument panel coincide with the instructions for the recommended maximum speed in the instructions for the saw;
  8. In the end, it remains to adjust the operation of the internal combustion engine of the saw at idle speed. To do this, slowly turn the bolt T against the clock hand until the motor runs stably and without dips. If the engine starts to stall, then the T bolt should be turned in the direction of the clock hand.

To adjust the carburetor on a chainsaw, you should work as accurately as possible with the adjusting bolts. Excessive tightening of the screws will lead to increased stress on the engine and other important parts of the garden tool.

How to flush the carburetor of a chainsaw?

To clean the assembly from stubborn dirt, it is best to use a product that is available commercially in pressurized cylinders. The kit includes a dispenser and a long thin tube that allows you to spray the product in any hard-to-reach places.

It must be remembered that cleaning the carburetor on a chainsaw is carried out using flammable chemicals. You need to work with them in a special protective mask and only in well-ventilated areas.

To clean the carburetor on a chainsaw, the unit will need to be partially disassembled. The throttle valve, adjusting screws, housing and other parts of the carburetor will need to be rinsed with a bottle cleaner and set aside until completely dry. Once all the elements are dry, the unit can be assembled and installed back on the chainsaw.

Chainsaw carburetor

Chainsaw carburetor Is an element that is responsible for mixing the air-fuel mixture. Not only the stability of the engine, but also the speed of the entire chainsaw depends on the condition and serviceability of this important unit. In this regard, each owner of a garden tool should study the design of the carburetor, as well as familiarize himself with the rules for its maintenance and repair.

Gasoline does not flow into the chainsaw carburetor

If the fuel does not enter the standard chamber, then this may indicate several breakdowns at once. The first step is to check the air and fuel filters. During long-term operation of the saw, these elements absorb a large amount of dust, which further prevents the infiltration of clean air and fuel. A slightly dirty filter can be cleaned with gasoline, but if the part is clogged with a lot of dust, then it will need to be replaced.

Another reason for the malfunction is the needle. This part sticks, especially in Chinese-made chainsaws. To fix the problem, in most cases it will be enough just to move the needle.

If no fuel enters the chamber, the saw owner should inspect the tool seals. After several months of using the tool, these parts lose their tightness. Over time, they begin to leak gas, as a result of which the instrument stops starting. Repair is carried out by replacing oil seals.

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The breather plays an important role when starting the saw. It is located near the saw’s gas tank cover, and performs 2 tasks at once. It maintains optimal air pressure and does not allow fuel to leak out. To check the breather, you will need to turn off the fuel pipe and see how much gasoline flows out. If it does not leak at all, then the standard breather is clogged with debris and dirt. In this case, you will need to clean the element and reinstall it.

If fuel does not enter the chamber, then you need to check the fuel line. Most often, a Chinese hose is used to complete a budget-class tool, which eventually loses its tightness. In this case, it will be necessary to replace the line, paying special attention to the tightness of the channel joints.

Chainsaw carburetor adjustment. What a beginner needs to know?

Initially, all adjusting bolts are in the factory positions. This ensures that the optimal amount of fuel and air is sucked in. However, due to prolonged use of the saw in difficult conditions, the factory settings of its carburetor may be violated. Even a slight movement of one of the bolts by 1/5 of a turn will seriously damage the saw motor. In this regard, the operator must constantly monitor that the adjusting bolts are in the optimal, factory-set, positions.

If for some reason the work of the node has been disrupted, then it will need to be reconfigured. For this, 3 adjusting bolts are provided in the assembly device. The first of them is marked with the letter H. It is needed to tune the engine of the chainsaw when operating at maximum speed. The second screw marked L is used to adjust the motor when running at low rpm. The third screw can be labeled T, S or LA. Its task is to configure the internal combustion engine when operating in idle mode.

Chainsaw carburetor tuning must be carried out with a completely serviceable engine. Immediately before adjustment, you will need to inspect the air filter, and, if necessary, clean or replace it.

Chainsaw carburetor device

Most modern chainsaws are equipped with nearly the same carburetors. They practically do not differ from each other, and work according to a similar principle. The only difference between cameras from different manufacturers is the material from which they are made. In expensive American, Swedish and German chainsaws, cameras are made of reliable alloys, on which protective coatings are applied. Cheap Chinese and Korean chainsaws are equipped with nodes made from cheap materials.

Each carburetor consists of the following elements:

  • Aluminum body with one-piece construction. Inside the body there is an inlet fitting, a main screw, an impulse channel, a bolt for adjusting the engine when idling;
  • Throttle valve. It is responsible for adjusting the amount of air required to enrich the fuel mixture;
  • Diffuser. Located next to the chamber inlet;
  • Sprayer. Designed to supply the fuel mixture directly to the carburetor chamber;
  • Float chamber. There is a float in it, which is triggered in case of insufficient fuel;
  • Jets. Are valves that are responsible for adjusting the amount of fuel.

This chain saw carburetor circuit is as simple and effective as possible. In some models of gardening tools, it can be supplemented with additional pipes, oil seals or filters.

The principle of operation of a chainsaw carburetor is quite simple. When the engine starts, the air damper located at the bottom of the housing opens. In this case, a vacuum is formed in the float and air chambers, caused by the movement of the piston. As a result, the standard diffuser is triggered, which begins to suck in air. The amount of intake air depends on the opening of the damper. When the piston is triggered, fuel begins to flow into the chamber through the inlet fitting. Its quantity and flow rate depend on the position of the nozzles.

Subsequently, the fuel in the air chamber begins to mix with air. After that, the finished air-fuel mixture passes through the intake valves, from where it is sent to the combustion chamber of the saw engine.

Why the chainsaw shoots the carburetor?

Often, chainsaw carburetor malfunctions are associated with loud extraneous sounds that come from the side of the unit. Ignoring them will lead to even more serious damage, which will be much more difficult to eliminate.

First of all, you need to understand the causes of extraneous sounds. The first of them is an incorrectly set ignition, due to which the used fuel does not have time to burn in the internal combustion engine cylinder in time. This leads to the formation of a short-term shooting noise that repeats with each cycle of fuel supply to the cylinder.

To eliminate the malfunction, you need to adjust the gap between the flywheel and the standard ignition coil of the chainsaw. To do this, remove the left protective cover of the plastic housing and clean the parts underneath. To the right of the ignition coil there are 2 screws, turning them counterclockwise will move the flywheel away from the standard coil. Next, you will need to attach a template to the side of the coil and start slowly turning the factory screws in the opposite direction. As soon as the built-in handwheel comes close to the previously installed template closely, turning the screws will need to stop.

After adjusting the ignition gap, you need to check the operation of the chainsaw. If she still fires, then you need to examine the candle. If carbon deposits have accumulated on it, then the part must be cleaned and completely dried.

Another reason the used chainsaw fires is the wrong proportion of the prepared fuel mixture. If it contains too little gasoline or engine oil, the garden tool engine will not be able to run smoothly. In this case, you will need to completely drain the fuel and prepare the mixture in accordance with the manufacturer’s instructions.

In some cases, a disruption in the supply of fuel to the engine cylinder may be caused by improper operation of the standard carburetor jets. In this case, you will need to adjust the carburetor and alternately check the operation of the tool at idle, low and high speeds.

What to do if gasoline does not flow into the chainsaw carburetor?

The first of the reasons for this failure is the clogging of the fuel filter with dust and dirt. This happens due to the presence of a large amount of harmful impurities in gasoline and used engine oil. Over time, they accumulate on the surface of the filter, due to which the filter loses its ability to pass fuel. To solve the problem, you will need to thoroughly clean the filter by rinsing it in a bath with a cleaning agent. If the filter has holes or other signs of wear, it must be replaced immediately.

The second reason for breakdown is contamination or breakage of the tube through which fuel is supplied to the carburetor. If the hose is not cut off, it will be enough to thoroughly blow it with compressed air from an aerosol for cleaning. If the tube is broken, it will need to be replaced. When installing the hose, the places of its joints with the fittings must be carefully treated with a sealant.

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There is another malfunction that occurs much less frequently than the previous two. It consists in a breakdown of the valve that regulates the rate of fuel supply to the carburetor. If dust or small chips get inside its mechanism, then the flap is blocked and remains in the closed position. Repair of the assembly can only be performed with the replacement of the valve, since it, most often, cannot be restored.

How to properly adjust the carburetor on a chainsaw?

Before setting up the carburetor on a chainsaw, you need to carefully prepare for the procedure. First of all, it is necessary to find in the operating manual the descriptions of the angles of rotation of the adjusting screws. If you turn the bolts at random, without adhering to the manufacturer’s instructions, this can lead to serious damage to the engine’s internal combustion engine.

The motor itself must be in perfect working order. The air filter must also be thoroughly cleaned before tuning. Otherwise, it will not be able to pass air in the volume required to enrich the fuel mixture, which will lead to an incorrect carburetor setting.

Assembly adjustment should be carried out on a level surface. The saw itself must be installed so that the saw head is positioned away from the operator’s feet and face. Immediately before tuning, you will need to remove the upper part of the protective plastic case of the instrument, as well as remove the foam rubber and part of the standard air filter. A thin curly screwdriver is required to complete the node setup.

You need to adjust the carburetor of the chainsaw in 2 stages. The first one is basic. During its execution on the switched off chainsaw with a cold engine, it is necessary to screw in bolts H and L alternately in the direction of the clock hand until it stops. After that, each of the screws will need to be unscrewed 1.5 turns in the opposite direction.

The final carburetor adjustment is carried out in the following order:

  1. First, you need to start the chainsaw and give it time to completely warm up the engine. In this case, the throttle lever must remain in the medium speed position;
  2. Further, the screw, which is responsible for the idle speed of the engine, will need to be slowly turned in the direction of the clock hand. This must be done until the internal combustion engine of the saw starts to work stably;
  3. If, during stable operation of the motor, the chain moves along the tire, then the same bolt must be slightly unscrewed in the direction against the clock hand;
  4. Then you need to connect a hand tachometer to the motor. With its help, you need to find high and low work of the internal combustion engine. To do this, the adjusting bolts H and L must be turned alternately in different directions until the device shows the indicators that are indicated in the operating instructions.

At the end, the chainsaw used will need to be turned off and started again. It should work stably at idle, and its chain should not rotate along the bus in this mode. When you pull the throttle trigger, the saw should quickly pick up speed, and when you release it, reset them.

Chainsaw carburetor device

Almost all carburetors used in the production of chainsaws have one and the same device. The only difference is the mechanisms with which Chinese garden tools are equipped.

As standard, the fuel assembly consists of the following parts:

  • Float chamber. This element is designed to continuously maintain the required amount of fuel. When the unit is in operation, the fuel is transferred through the built-in jet to the sprayer;
  • Tube. Through it the fuel flows in portions into the chamber. The fuel supply is regulated by the position of the built-in factory shutter;
  • Atomizer. This part is necessary for injecting fuel into the intake air stream.

The principle of operation of a chainsaw carburetor is quite simple. During operation of the unit, air is sucked in by the tube and passes through it at a speed that is regulated by a built-in damper. With the opening of the damper, the float located in the chamber is actuated. After passing through the diffuser, the air mixes with the fuel and is instantly atomized. The air-rich, high-quality fuel mixture then passes through the intake duct and into the engine cylinder. The diagram will clearly show the operation of the carburetor.

The fuel in the unit circulates under the influence of pressure. In the float chamber, it is close to atmospheric, and in a standard suction tube, the air is more rarefied. Due to the difference in the generated pressure indicators, the fuel mixture enters the pipe. The more the amount of fuel, the higher the speed the engine of a household chainsaw can create.

The device and adjustment of the chainsaw carburetor

The carburetor is one of the most important parts of any modern chainsaw. Its main task is to mix the fuel mixture with air, as well as to further supply the finished fuel to the cylinder of the gas engine. During the operation of the chainsaw, its carburetor is constantly working, therefore, over time, this unit begins to need adjustment and flushing. Performing these procedures is quite simple, if you are extremely careful and follow the correct procedure.

Chainsaw carburetor adjustment

This procedure is necessary specifically in cases where the household garden tool does not start or, after starting, immediately stalls. Chainsaw carburetor adjustment is also needed when its power has dropped or the amount of fuel consumed has increased significantly.

For self-adjustment, each manufacturer includes adjusting screws in the complete set of their garden equipment. The bolt, marked with the letter H, is used to adjust the position of the main jet and the operation of the internal combustion engine at high speeds. Bolt L is required for basic adjustment of the position of the built-in motor-driven idle speed. Accordingly, the T screw is required by the owner of the chainsaw to quickly adjust the idling of the factory engine. In some cases, this bolt is also marked with the letters S or LA.