Trimmer Speed Adjustment
Carburetor for trimmer: device, do-it-yourself tuning When do you need to adjust the carburetor of a household trimmer? Carburetor device lawn mowers, do it yourself carburetor adjustment
Carburetor for trimmer: device, do it yourself setting
Stable and efficient operation of a household trimmer largely depends on the quality of the fuel used by the operator. The filled fuel mixture must be enriched with air. A built-in carburetor is responsible for this in the basic device of the lawn mower. This knot is one of the main elements of the streamer, so the operator must constantly monitor its serviceability and settings. Otherwise, the trimmer will lose its performance and may completely fail.
Lawn mowers carburetor device
The standard design of any gasoline trimmer necessarily includes a fuel system, the basis of which is the action of a regular carburetor. Its design and initial principle of operation are almost the same for all lawn mowers, regardless of their design features and purpose.
The lawn mowers carburetor consists of an all-metal aluminum housing that protects the internal components of the unit from moisture, small debris and dust. In the lower part of the body there is a built-in diffuser, the second name of which is “Venturi nozzle”. The main function of this standard part is to supply air in the amount required by the fuel unit to enrich the fuel. A diffuser works according to a simple principle: the smaller its diameter becomes, the more intensively the air is sucked in. This is due to the fact that in the zone of the smallest diameter the level of air vacuum becomes maximum.
The upper part of the built-in factory diffuser is pre-equipped with fuel pipes, through which, under the influence of air, the fuel mixture is drawn in. The rest of the carburetor parts: standard adjusting screws and a fuel pump, can be located both inside and outside the carburetor.
The lawn mowers carburetor device includes a throttle valve, the main task of which is to regulate the volume of intake air. The larger the amount of air, the higher the rated power of the trimmer power unit. Another function of the damper is to facilitate cold starting of the engine. If this is the first time the mower is started after a long period of inactivity, the shutter must be closed. Immediately after starting the motor, the part must be opened, otherwise the internal combustion engine will stall.
The carburetor for the trimmer is equipped with an impulse channel that connects the internal cavity of the engine crankcase with the impulse chamber of the pump. The piston located in the cylinder of the motor creates reciprocating movements, which leads to gradual changes in pressure inside the crankcase. At the same time, the membrane is set in motion. Thus, the action of the pump is fully synchronized with the operation of the power unit.
The diaphragm of the standard carburetor takes an active part in the suction of fuel. It enters the fuel unit through the fitting. The fuel then passes through the integrated inlet and outlet valves, then through the strainer and fuel pipe. The fuel then flows near the needle and gradually fills the chamber equipped with the control diaphragm.
The standard carburetor trim valve is connected to the diaphragm with a lever. Below the built-in membrane is a cavity into which air is sucked in through a special opening.
The lawn mower carburetor works on this principle in stages. This ensures continuous operation of the fuel unit and uninterrupted fuel supply to the cylinder of the standard power unit.
When is the carburetor setting of the household trimmer required?
Adjust the built-in trimmer carburetor when:
- Running in a new engine, during which 4 to 5 liters of fuel mixture were used;
- Sudden changes in weather;
- Changes in air pressure. For example, when the lawn mower is often used in mountainous areas;
- Long-term simple trimmer;
- Intensive growth of loads on the power unit of lawn mowers;
- Arbitrary unscrewing of the built-in adjusting screws of the carburetor. This causes increased vibration of the internal combustion engine;
- Changes in the quality of the components of the fuel mixture;
- Pouring fuel with a carburetor, resulting in an increase in fuel consumption;
- The regular appearance of a thick layer of resinous deposits and carbon deposits on the surface of the electrodes of a standard trimmer spark plug;
- Starting the engine and its arbitrary shutdown or slow set of revolutions;
- Lack of fuel flow into the cylinder of the power unit;
- An increase in the volume of emitted waste gases.
The lack of timely adjustment of the carburetor threatens with serious damage to the trimmer, up to the complete failure of its factory engine.
Signs of imbalance
Debugging the carburetor must be done during the manufacture of the device. As a rule, the owners will learn about the need to adjust the fuel supply with their own hands only after serious enough breakdowns, in the process of correcting which, the module was removed and, for example, cleaned.
Signs of a configuration failure are the following:
- Starts, but the engine immediately stalls. Since the engine can only work when a certain amount of gasoline is supplied, if the fuel is too “lean”, that is, the supply channel is blocked, the engine will stop;
- Too high fuel consumption, a lot of exhaust gases. The result of incomplete combustion of the mixture. In this case, on the contrary, there is too much fuel and the mixture is too dense.
Principle of operation
A carburetor is a power system module in which liquid fuel and air are mixed before being fed into the engine cylinders. Mixing and feeding are adjusted accordingly depending on the tool and its mode of operation.
The carburetor device for lawn mowers is the same for almost all cases. It belongs to the category of float devices. The latter provide stable parameters of ready-made mixtures.
The principle of the module is as follows.
- Air enters the body of the air damper tube. The latter increases or decreases the air flow depending on its position.
- In the area where the hole for supplying gasoline is formed, the tube has a narrowing. A diffuser. Here the flow rate increases.
- Fuel from the float chamber is fed through the nozzle into the tube. The float level determines the amount of fuel supplied. Since the pressure in the chamber is normal, and in the tube it is low due to the greater rarefaction of the air, gasoline is sucked in through the nozzle.
- The accelerated air flow picks up the fuel and sprays it, forming an air-fuel mixture of the desired density.
- The mixture is sucked into the cylinder through the pipeline.
The more open the air damper in the tube, the higher the density of the air flow, which means more fuel enters the cylinder. Adjusting the carburetor of lawn mowers is reduced to setting such a ratio of flaps, at which the density of the fuel mixture becomes optimal.
Adjusting and repairing the carburetor lawn mowers
The trimmer does not belong to complex household appliances, therefore most of its breakdowns are mechanical in nature and are quite successfully eliminated with their own hands. Even if the engine fails for serious reasons. Damage to the piston ring, for example, repairs are reduced to replacing the part.
But even with a relatively simple design, such a part of the device as the carburetor needs to be adjusted.
Adjusting the fuel supply at minimum speed
Before you start tuning the carburetor of the petrol trimmer, you need to warm up the engine to operating temperature.
Fuel adjusting screws
To do this, we start the internal combustion engine and, at idle, let it run for 10-15 minutes. In the first step, with the trimmer working, slowly tighten the screw “L” until the start of intermittent operation or until it stalls. Next, unscrew the screw ¼ of a turn and check the maximum speed set. If the lawn mower reaches high revs quickly and easily, this will be the most economical mode. In most of the models on the market, the fuel screw “L” is turned clockwise, but there are trim tabs where the decrease and increase in the supply of the mixture occurs in the opposite order.
Carburetor Trimmer Adjustment
The initial step in restoring the correct operation of the fuel system is to clean the air filter.
Trimmer carburetor with screws
Experts recommend rinsing it in a solution of water and detergents after every 10-15 hours. Direct adjustment of the carburetor trimmer is done with three adjusting screws:
- Fuel adjustment screw (“L”);
- High speed adjustment screw (“H”);
- The screw responsible for the engine idling (“T” or “AT”).
Adjusting the maximum speed screw for lawn mowers
After restoring the fuel supply at minimum speed and adjusting the idle speed, it is necessary to check the stability of the mechanism at an increased speed.
Tuning at maximum speed
The motor is adjusted at high speeds in order to protect against overheating and to reduce hand fatigue when pressing the accelerator button. If the internal combustion engine is unstable at maximum speed, then the screw “H” must be tightened slowly until smooth and precise operation is ensured.
During the operation of the lawn mower it may be necessary to readjust the fuel screw (“L”) for optimal speed gain.
From personal experience
Idle speed adjustment
We start adjusting low speed. Screw number 2 limits the return movement of the throttle lever. By turning it, we increase the idle speed, unscrewing it, we decrease it. Adjust so that the engine runs confidently at low revs and even a little accelerated (for better starting), but so that the line reel or knife does not rotate, and there is a sufficient reserve of revolutions before they start spinning. If the engine starts poorly, increase the idle speed even more.
Fuel supply adjustment
Begin to slowly tighten the fuel mixture adjustment screw until the engine starts to stall or stalls if you do not have time to catch the moment. After that, unscrew the screw a quarter of a turn if the engine has not stalled, or half a turn if it stalled. Start the stalled engine. Check by opening the throttle as the engine picks up speed. Continue to unscrew screw # 1 by a quarter of a turn until the engine starts to accelerate steadily during gas blowing. This will be the moment of the most economical stable engine operation. For the PRORAB-8406 petrol trimmer, the adjusting screws are turned clockwise, unscrewed. Counterclockwise, for some other brands of lawn mowers it may be the other way around.
Carburetor adjustment FORTE lawn mowers
The gasoline lawn mower has been successfully used for a long time in a variety of industries: for lawn maintenance in private plots, in housing and communal institutions, landscaping organizations, agriculture and forestry. The main competitive advantages of the products. Low maintenance costs, increased reliability and ease of use.
Engine. The most important component of any technique. And so that it always works in the optimal mode for itself, it is recommended to fine-tune the carburetor.
How to repair the carburetor of lawn mowers with your own hands and why do they recommend doing this? First of all, to make sure that the engine is working properly and that the maximum productivity of the tool is ensured 100%.
Forte Lawn Mowers Carburetor Setting:
1. Start the engine of the device and let it warm up for 10 minutes (if you observe the rotation of the cutting element at idle speed, turn the idle screw in the opposite direction, turn until the spool stops turning).
2. Gently rotate the right and left needles to the middle position. Important! Never twist the stopper. This could damage the engine).
3. There are 3 adjusting screws to adjust the carburetor:
- Right H. Low speed screw
- Lower T. Idle screw
- Left L. High speed screw
Right screw H. First of all, the low speed screw is adjusted.
Find the highest idle speed by slowly turning the screw to the left or to the right. After finding the maximum rpm position, turn the screw counterclockwise на turn.
Note: FORTE lawn mowers are shipped from the factory with the right screw completely unscrewed (0.5 turn). At this stage, he should be looking at “11 o’clock.”
Bottom screw T. Responsible for adjusting the engine idle speed. Turning the screw counterclockwise decreases the number of revolutions. Counterclockwise. Increases.
Correct adjustment is considered only if:
- Cold engine at idle running stably without jerking
- A hot engine gives out understated revolutions in idle mode
- Sufficient headroom remains before the cutting system starts to work
- Stable engine operation in any position
Note: From the FORTE factory, the lower screw H (idle), from a fully tightened state, was unscrewed by 8 revolutions and “2 hours” (at this stage it should be). The recommended idle speed for FORTE engines is 2900 rpm.
Left screw L. Fine adjustment of the highest idle speed.
Important! The engine of FORTE petrol lawn mowers should not run at maximum speed for more than 10 seconds.
Open the throttle, start the engine and lightly turn the screw clockwise until the engine speed decreases.
Then slowly turn the screw L in the opposite direction until the engine starts to shake.
Finally, turn the screw clockwise a short distance again until the mower engine starts to operate in the appropriate mode for itself.
Do-it-yourself lawn mowers carburetor adjustment
Lawn mowers, like all gas powered garden tools, are not difficult to maintain. It is possible and necessary to repair, configure yourself. For example, adjusting the carburetor of a lawn mower with your own hands is a matter of five minutes.
A lawn mower carburetor is a unit in the power system. In it, like any carburetor, there is a process of mixing air and fuel (gasoline) for further supply to the engine cylinders.
The main problems and malfunctions of the carburetor.
Mesh filter. There are often only two problems with this element:
In order to find out the cause of the breakdown, the fuel filter cap is unscrewed to remove the strainer. If dirt just accumulates on it, then flushing in gasoline or blowing will help.
If there is visible damage to the mesh filter, it is imperative to install a new one. There may also be damage to the fuel supply pipe (during repair, they practice checking this element).
The carburetor starter in most cases does not function due to blockages. Use acetone or the same gasoline for flushing.
Blowing compressed air into clogged carburetor parts is an acceptable and convenient repair practice.
Lawn mowers carburetor device
The basis of the carburetor for lawn mowers is an aluminum body. It contains a diffuser (hole with internal contours). Air is blown through this hole. The flow rate of oxygen (air) depends on the cross-section (orifice) of the diffuser.
The diffuser is equipped with fuel channels. Fuel is drawn in from them using an air stream.
Outside the carburetor is installed:
- Fuel pump;
- Jet system;
- Fuel-air mixture control system;