Overflows carburetor on trimmer adjustment

Principle of operation

The procedure for pumping and filtering fuel in the engine of the lawn mowers is as follows.

  • The throttle valve controls the amount of air supplied to the diffuser. The more air is supplied, the more oxygen the gasoline needs to burn, and the more power is generated in the form of heat. The heat energy is further converted into mechanical.
  • The diaphragm pump delivers the required amount of gasoline.
  • Next, gasoline passes through the engine choke.
  • Fuel flows through the intake and exhaust valves.
  • Fuel filtration is carried out using a mesh filter.
  • Through the needle valve, it also enters the chamber with the membrane.

The staging of the carburetor is as follows.

  • Air enters the duct with an air damper. The damper sets the required air flow rate.
  • In the gasoline injection unit, the diffuser is narrowed. this is necessary to give a higher air flow rate.
  • The fuel passes through the compartment with the float and bypasses the jet, enters this narrowing of the tube. The float chamber doses the gasoline supply. In this compartment, the pressure is in equilibrium. In a narrowed tube, it goes down. Due to the difference in both pressure values, gasoline and passes through the jet.
  • The accelerated flow sprays gasoline, converting it into aerosol vapors. The resulting gasoline-air mixture is ready for ignition in the combustion chamber.
  • Having passed through the fuel line, this mixture is in the carburetor cylinder.

Conclusion: to set the required power, first of all, you will adjust the rate of fuel combustion using the air damper. If the gap is too small, and oxygen in such a mixture is less than 10%, the fuel does not burn, therefore, the engine will not start or will immediately stall.

In the case of buying a Chinese trimmer, it is worth considering that it does not differ much from European ones. the same 2- or 4-stroke engine and drive.

However, they save on the quality of parts, forcing the consumer to change them more often. Check what compatible parts non-Chinese companies offer for your device.

Fuel pump problems

overflows, carburetor, trimmer, adjustment

The reasons for membrane deformation can be the following:

  • long work of the trimmer;
  • use of unsuitable fuel;
  • ingress of gases into the impulse channel.

As a result, diaphragm damage reduces pump performance and, as a result:

  • depletion of the combustible mixture occurs;
  • it is difficult to start the engine;
  • there are interruptions in the operation of the motor;
  • the piston is damaged.

Also, the above-described consequences for the engine can cause clogging of the pump cavity on the impulse side. In this case, dirt enters the membrane through the impulse channel.

To remove the blockage, you will have to disassemble the carburetor and clean the membrane.

When to adjust

Carburetor adjustment is necessary in the following cases:

  • the new engine was run-in (4-5 liters of fuel mixture were used);
  • the composition of the fuel has changed (brand of oil and gasoline);
  • the weather has changed (it became hot, cold);
  • the rarefaction of air has changed (applies to mountainous regions);
  • after long-term storage;
  • increased load on the engine (after tool change, etc.);
  • due to vibration, the adjustment screws spontaneously unscrewed;
  • fuel consumption has increased, the carburetor overflows fuel;
  • carbon deposits quickly appear on the spark plug electrodes (while the fuel mixture is prepared correctly);
  • the engine starts and immediately stalls or gains momentum poorly;
  • no gasoline enters the cylinder;
  • large amount of exhaust gases.

Adjustment lever defective

This breakage occurs when the contact surface of the lever wears out.

The abrasion of the contact surface occurs due to the presence of abrasive particles in the gasoline or due to strong vibration of the engine during operation. This defect in the adjusting lever causes problems with the intake, as well as improper idling of the engine.

Failure of the adjusting lever

The wear of the contact edge of the lever is a consequence of an incompletely purified fuel, into which grains of sand or particles of clay, metal or other inclusions that are not soluble in liquid hydrocarbons have gotten. There is a problem with fuel injection, the engine does not function without load.

Carburetor cannot be adjusted

The fact that the adjustment is too coarse (it is not possible to accurately set the parameters) are to blame for the springs on the adjusting screws. A lawn mower or trimmer manufacturer may supply unnecessarily thick and stiff springs. You can find others either in workshops where similar equipment is repaired, or purchased from any dealer or official representative of the company that produced the motor for your trimmer or power scythe.

How to adjust the carburetor of lawn mowers?

a lawn mower or trimmer, despite its relative simplicity (compared to a car engine), sooner or later fails. There comes a time when long downtime and restarts of the gasoline unit cannot be avoided. maintenance is needed. In advanced cases, repair is required, or rather, replacement of worn-out parts with the same new ones. Until you are faced with the need to replace your spent parts, carburetor maintenance is required. cleaning, rinsing, reconfiguring mechanisms.

Accelerator pump does not work

In the event of problems with the accelerator, fuel may not flow or may be supplied in the form of a short and sluggish jet, which leads to delays during acceleration. In the first case, the reason lies in the blockage of the fuel nozzle of the accelerator pump or the adhesion of the ball to the check valve sleeve. With a bad jet, the ball may hang or a leaky diaphragm connection between the carburetor body and the cover. The way out of the situation is to clean the parts and check their condition.

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Throttle valve adjustment

DZ is adjusted after removing the carburetor from the engine in the following sequence:

    Rotate lever A counterclockwise.

Adjustment of the starting mechanism and air damper

First you need to prepare a 5 mm template and a piece of wire 0.7 mm thick, after which you can start setting up:

  • Remove the filter housing and remove dirt from the carburetor, for example, with a rag.
  • Pulling out the suction in the cabin.


If shots are heard from the carburetor, the problem is usually caused by excessive fuel entering the carburetor. The malfunction manifests itself in the form of sharp twitching while driving. The solution to the problem is to flush the assembly.

Pours gasoline

The essence of the problem boils down to the fact that gasoline enters the mixing device in a larger amount than necessary, and the check valve does not discharge excess fuel into the gas tank. As a result, drops of gasoline appear on the outside of the carburetor. To eliminate the malfunction, it is necessary to clean the fuel jets and their channels.

Who produces and on which models VAZ is installed

The DAAZ 2107 carburetor was manufactured at the Dimitrovgrad Automobile Unit Plant and installed on different Zhiguli models, depending on the product modification:

  • 2107-1107010-20 were equipped with engines of the latest versions of the VAZ 2103 and VAZ 2106 with a vacuum corrector;
  • 2107-1107010 were put on “fives” and “sevens” with engines 2103 (2106);
  • carburetors 2107-1107010-10 were installed on engines 2103 (2106) with a distributor without a vacuum corrector.

How the carburetor works

The functioning of the device can be described as follows:

  • Fuel from the gas tank is pumped by the gasoline pump into the float chamber through a filter and a valve that determines its filling level.
  • From the float tank, gasoline is fed through the nozzles into the carburetor chambers. Then the fuel passes into the emulsion cavities and tubes, where a working mixture is formed, which is fed to the diffusers by means of atomizers.
  • After starting the motor, the electromagnetic valve closes channel XX.
  • During operation at XX, fuel is taken from the first chamber and passes through a nozzle connected to the valve. When gasoline flows through the XX nozzle and part of the transition system of the primary chamber, a combustible mixture is created, which enters the corresponding channel.
  • At the moment of opening the DZ, the mixture is injected into the carburetor chambers through the transition system.
  • The mixture from the float tank passes through the econostat and enters the sprayer. When the motor is running at maximum speed, the accelerator starts to function.
  • The accelerator valve is opened when filling with fuel and closes when the mixture supply is stopped.

Overflows the carburetor: possible causes

Overflowing fuel in the carburetor is a common phenomenon, and certainly causing considerable inconvenience to those motorists or motorcyclists who have suffered from it. Most often, such a “sore” is found on Solex and Azon carburetors installed on many models of cars from AvtoVAZ and on all fuel supply units for mopeds, motorcycles or lawn mowers.

Definitely, there is nothing good in the fact that the carburetor fills, but if the problem overtook you, then you need to get rid of it. To do this, it is enough to understand the essence of this malfunction, the reasons for its occurrence and methods of elimination. About this and much more, as for the fuel overflow in the carburetor, we will burn out in the article below.

Signs of problems with the fuel level in the carburetor

Before starting to repair any part of a car or other vehicle, it is important to make sure that the problem is caused by this or that node. In the case when the carburetor is flooded, it is very simple to check the malfunction of this particular unit. it is enough to analyze the behavior of the car and pay attention to some aspects of its functioning. In particular, in case of a problem with fuel supply, the following will be observed:

  • difficulties with starting the engine, especially with a well-heated engine;
  • unstable or increased idle speed;
  • problems with setting “idle”;
  • trickles or real puffs of black smoke from the exhaust pipe;
  • failures with medium and strong pressing on the gas pedal;
  • black velvety carbon deposits on spark plugs.

Note that such symptoms are also observed when fuel is poured from the carburetor of a chainsaw, a motorcycle, a moped, a car, and even a tiller. However, nodes with a small and, as a rule, parallel fuel system, which are equipped with a multicultivator, moped or scooter, also have another sign. the presence of gasoline in the air filter. If such a symptom occurs, then it can be guaranteed that the carburetor is overflowing and requires some measures.

Overflow reasons

Let’s say that the carburetor began to mercilessly pour gasoline, there is no doubt about it. What to do next? First of all, it is important to establish the cause of the problem. By answering the question “Why does it fill the carburetor?”, Any vehicle owner will be able to fix the malfunction on his own. Often the reason for such a breakdown is one of the following:

  • There is a malfunction of the needle valve. A carburetor on a moped and similar nodes on a trimmer or similar devices often get sick with such a “sore”. A malfunction of the needle valve often appears due to the loss of its hermetic state, in which it closes the fuel channels in a timely manner and fully, thereby metering its supply. If the valve is badly worn out or “stuck” in the open position, gasoline overflow cannot be avoided. You can check this unit for correct functioning by supplying rarefied air to it; during normal operation, the needle should stably close the fuel paths and not let air through;
  • The float in the float chamber is either leaking or hitting the walls of the carburetor. The owner of any carburetor unit is not insured from a problem of this kind. You can check the normalness of the float by removing the cover of the float chamber and a detailed inspection of the unit;
  • The level in the float chamber has risen or the one that was present all the time has ceased to be relevant. This is often the case when a motorcycle, moped or car has a faulty unit that increases fuel consumption for a long time. The part has been replaced or repaired successfully, but the gasoline continues to be supplied in the same quantities. As a result, it turns out that the carburetor “pours”. Checking for the presence of such a problem is carried out exclusively by an empirical method, that is, by “playing” with the fuel level in the float chamber;
  • The fuel pump is faulty. Perhaps, this is also the problem from which you will not be able to insure yourself. It appears for only one reason. the gas pump is out of order due to its individual elements. In such a situation, it remains only to disassemble, inspect and repair the broken part;
  • A non-return valve has broken, returning gasoline to the fuel line when overflowing in the float chamber. Relevant for any Solex carburetor and similar units. You can check for a problem with the “return” by disassembling it, visual inspection and blowing it with compressed air. If such manipulations did not correct the state of affairs and there are no other problems, then you should think about replacing the check valve.
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The reasons described above for overflowing the carburetor on a scooter, car or other unit are found in case of a breakdown of this kind in the order of 80-90% of all cases. Much less often, gasoline overflow occurs due to a malfunction or improper adjustment of individual elements of the fuel distribution unit. Mostly rubber seals of jets, economizers of power modes, throttle valves, solenoid valves, carburetor gaskets and screws for adjusting the mixture quality are affected. Checking the functioning of these elements is carried out by disassembling the carburetor and its detailed inspection with the adoption of subsequent repair measures.

Elimination of overflows in the carburetor

Quite a lot can be written about how to eliminate carburetor overflow. Our resource decided not to describe each methodology for solving the problem separately, but to present how to act when it appears, clarifying all the details. In general, the repair procedure is as follows:

  • First, you need to check all components that can be checked without removing the carburetor, then repair them or replace them if the problem is identified. These elements of the fuel system include:
  • fuel pump (disassembled, the integrity of diaphragms and other elements is checked);
  • check valve (its appearance is examined, integrity violations are detected);
  • carburetor gaskets (check for gasoline smudges at their locations);
  • solenoid valve (to check, it is enough to unscrew the valve and connect it to the network, if after 30-120 seconds the needle does not move a few millimeters, the unit needs to be replaced).

If no problems are identified, the carburetor is dismantled.

  • Having removed the carburetor, you must:
  • First, check the operation of the throttle valve and the integrity of the needle diaphragm;
  • Secondly, to disassemble the assembly, checking the integrity of the gaskets, nozzles, their O-rings, floats, locking needles and other elements, the failure of which can provoke an overflow;
  • Thirdly, clean and blow out all fuel passages of the carburetor.
  • Naturally, if problems are identified, they are eliminated, the part is reassembled and put into operation. In this case, before installing the carburetor, it is important to set it up correctly. Everything related to setting the carburetor is individual for each unit, so we will not focus on this. Note that in some cases it is enough to adjust the screws of the mixture quality or the dimension of the nozzles, and in some cases you will have to “play” with the level of the float chamber or the position of the diaphragm needle.

  • Well, at the last stage, if the measures presented above did not work, it remains only to take the carburetor or take the faulty transport entirely to a specialist. Do not forget that a carburetor is a very complex device, so sometimes only a professional can handle its repair.
  • We strongly recommend that you resort to the last step of the repair as a matter of priority, if at the sight of the carburetor you have a thought. “What to do, I don’t understand anything about this…”, or something like that. In such a situation, it is better not to aggravate the problem with your own repair, but to trust a specialist, even if it costs some money.

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    In general, it is not so difficult to deal with a gasoline-pouring carburetor. The main thing in the parsing process is to act taking into account your knowledge and the provisions presented above. We hope that today’s material has provided answers to your questions. Good luck with the repairs and on the roads!

    Fuel supply adjustment

    Adjustment at maximum speed

    Further, to fully adjust the carburetor, the lawn mowers need to adjust the maximum speed. It will not be superfluous to look into the instruction manual of the tool and see the maximum value of the revolutions. Most accurately, this number will help determine the tachometer. If such a device is not at hand, we tune it by ear. Having barely determined the maximum rpm value by ear, we begin the adjustment. The screw for limiting the maximum speed will help in this matter. Check the operation of the engine at maximum speed. If it is necessary to reduce the speed, it is necessary to loosen the fixing nut and unscrew the screw. If the revolutions are too high, then you will need to screw in the screw. These steps must be done in order to protect the engine from overheating. It is necessary to turn the screw until a clear smooth engine operation is established.

    After the work done, if everything is done correctly, the stable operation of the tool is ensured.

    This will be understood by the following signs:

    • The cutting element will stop rotating at idle speed;
    • Fuel consumption will decrease.

    How to clean, adjust, and fix common carburetor problems on a Stihl FS90 trimmer weedeater

    Idle speed adjustment

    Following the adjustment of the fuel supply, we take up the idle speed adjustment. To do this, the corresponding screw must be adjusted so that the engine runs slightly accelerated at low revs. But it is necessary to monitor the immobility of the reel with fishing line and knives. Before starting their movement, there should be a few turns in stock. The movement of the spool and knives can subsequently lead to rapid wear of the clutch. Noticing that the engine does not start well, you need to increase the number of idle revolutions. As the revs increase, the fuel mixture is saturated with air, which leads to a loss of power.

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    The main signs of correct idling:

    • Stock of turns for the trimmer head;
    • Uninterrupted operation of the engine even when changing position (sharp rise or fall of the knife);
    • Quiet operation of the engine on a cold run;
    • No increased rpm of a hot engine.

    Adjusting the carburetor trimmer

    lawn mowers have long been included in our lives as a very useful tool and a great alternative to the usual scythe. lawn mower and lawn mower are the same tool. And trimmers are gasoline, and there are electric. In this case, we will focus on gasoline. This unit is quite simple to operate, but it has its own characteristics. lawn mowers are equipped with an internal combustion engine. The carburetor for lawn mowers is a very important part of the tool. The main task of the carburetor is to ensure the flow of air-enriched fuel into the engine cylinder. The most important thing here is to maintain the balance of fuel and air. The article will tell you about the signs indicating the need for adjustment, how to adjust the carbrator on the trimmer.

    It is allowed to adjust the carburetor trimmer on your own, having previously studied the device of the unit. As a rule, a detailed description of the constituent assemblies of the tool is in the instruction manual. An experienced craftsman is able to even determine by ear that there are shortcomings in the work of lawn mowers. The sound of the motor, when properly tuned, should be perfectly smooth. If you can clearly hear screeching sounds, then the mixture is oversaturated.

    Cases indicating the need for adjustment:


    • If a fuel mixture of a different composition is used;
    • With a long break in operation (the lawn mower lay idle for a long time, and even before the new season after winter);
    • After completion of the equipment break-in process (usually after using 4-5 liters of fuel)
    • When weather conditions change (this item is relevant for);
    • Poor engine starting
    • If fuel consumption has increased sharply;
    • An increase in the amount of exhaust gases;
    • Slow set of revolutions by the engine;
    • If the fuel mixture does not flow.

    Carburetor setting lawn mowers with three adjusting screws

    Place the lawnmower on a flat, stable surface before starting work. Turn the chain in the opposite direction. Lawn mowers are available with two and three adjusting screws. The two screws are most often equipped with tools made in China. Consider adjusting the carburetor of a lawn mower with three screws.

    Carburetor setting lawn mowers with three adjusting screws

    The air filter must be rinsed before proceeding with the carburetor adjustment of the lawn mower. Cleaning is carried out with water with the addition of detergent or soap, and, if necessary, a new one is installed. Often, blockages are to blame for poor carburetor performance. As a preventive measure, it is recommended to clean the filter after every 10 hours of tool operation. Do not forget to check the condition of the candle, if there is carbon deposits, you need to clean it. Candles are consumables and have their own resource. To ensure good engine performance, lawn mowers need to be replaced periodically. Next, we evaluate how well the carburetor is attached to the cylinder-piston group. After finishing the preparatory manipulations, you need to start the engine. Let the engine run for 5-10 minutes. Then you need to identify how many adjusting screws on your instrument.

    The petrol trimmer has the following adjusting screws:

    • Idling adjustment screw;
    • Fuel mixture adjustment screw
    • Maximum speed limiting screw.

    Carburetor setting lawn mowers with two adjusting screws

    Adjusting the carburetor for two-screw lawn mowers is much easier than described in the first option. It should be noted, however, that this setting is less accurate. Before starting the setup, you must remember the factory settings of the lawn mower After a while, the engine starts and runs for several hours. Although on some instruments, 10-15 minutes of work is enough to set the necessary parameters.

    Carburetor setting lawn mowers with two adjusting screws

    First you need to start the engine at low speed. If, during operation, the chain moves along the bus, then this is not the norm. You need to adjust the screw so that the chain stops moving.

    Next, you need to go to medium speed. After which the engine can smoke. The adjusting screw will also help eliminate this nuisance. By tightening it harder, the fuel mixture, which is less enriched, will begin to flow into the engine. After that, the smoke will disappear. But the turnover will increase. Adjustments must be made until smooth, precise operation without jerking is achieved.

    After all the necessary settings have been made, it is necessary to let the trimmer work in real conditions for more than one hour. After a while, it would be good to check if all the components are working correctly. If deviations are found, they need to be eliminated.

    An indicator that the adjustment has been completed successfully will be residual combustion of fuel and a slightly brownish color of the plug. The color of the carbonized candle is darker.

    Adjusting the carburetor for lawn mowers is a very important preventive measure that must be carried out every time such a need arises. As described above, such a need may arise quite often. By the way, the screws that have loosened from vibration can also serve as a reason for tuning. In order for the tool to serve for a long time, you must always follow the instructions for use of the lawn mowers, use the correct fuel mixture.