Stihl Fs 38 Lawn Mowers Carburetor Adjustment

Chainsaw Stihl 180; device and adjustment of the carburetor The main elements of the carburetor chainsaw Stihl MS 180. Methods of adjustment, removal, disassembly and repair. Troubleshooting tips.

Distribution chamber

In the distribution chamber, as in the fuel pump, there is also a membrane that opens and regulates the fuel supply by pressing a special rocker, which raises its needle valve.

Stihl fs 38 lawn mowers carburetor adjustment

The cover of the chamber is the compensator body, which is attached to the carburetor with four screws, a gasket is installed between the body and the cover, which increases the height of the chamber and is responsible for sealing.

Dismantling the carburetor Stihl 180

In order to purge, change the gaskets or the needle valve, the carburetor must be disassembled. To do this, unscrew 4 screws on the expansion joint cover and one on the fuel pump.

Having opened the case, you should be extremely careful, because if debris gets inside the carburetor, it will make its work impossible. The thickness of the channels in it is comparable to the thickness of a thread or even a human hair.

For the repair of the Stihl 180 carburetor, can be seen below. In it, the master tells in detail about the problems and clearly demonstrates the entire repair process.

Adjusting the Stihl 180 carburetor

The carburetor of the Stihl 180 chainsaw, indiscriminately, can only be adjusted by the number of idle revolutions. It is impossible to increase or decrease the fuel supply in different modes using special screws. The manufacturer restricts access to adjustments and does not install these screws. How to adjust the carburetor to the correct idle speed is described in great detail in the manufacturer’s instructions.

In the event of certain malfunctions, and with experience, it is possible to increase or decrease the fuel supply by increasing the clearance when opening the needle valve.

To increase the flow, the rocker arm of the needle valve in the distribution chamber must be bent up, and to decrease, down. This regulates the stroke of the needle and, accordingly, the throughput of the valve.

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.

READ  How to Adjust a Carburetor to a Husqvarna 125r Trimmer

But even with a relatively simple design, such a part of the device as the carburetor needs to be adjusted.

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.

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.

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.

READ  Installing Fishing Line On Stihl Fs 38 Trimmer

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:

  1. Blockage.
  2. Breaking.

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;

 

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:

  1. Blockage.
  2. Breaking.

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.

Adjusting the carburetor lawn mowers Stihl FS 38

  • First you need to stop the engine;
  • Then install the mowing head;
  • The next step is to check the air filter, and if the filter element is not in good condition, it should be replaced;
  • It is necessary to completely turn the idle speed adjusting bolt clockwise until it stops, and then 1.5 turns counterclockwise;
  • After starting the device, you should wait until the engine warms up;
  • Using the idle stop bolt, the owner must correct the idle speed to immobilize the cutting tool.
READ  Which Gasoline Lawn Mower To Choose

It is not difficult to deal with all the procedures, the main thing is to get serious about the matter and tune in to work. Over, many owners note that you can independently carry out not only tuning the carburetor, but also replacing parts. Downward-looking schemes will be excellent assistants in this matter.

The STIHL FS 38 trimmer. A functional unit you can trust

The STIHL FS 38 trimmer is probably familiar to all fans of quality garden equipment. People who have once experienced the brand’s products in practice rarely switch to products from other brands, because German quality conquers completely and completely.

This lightweight gasoline device is quite compact, it is ideal for cleaning small backyard areas. Many private sector owners prefer this particular “helper”, because it does an excellent job and demonstrates a high level of productivity.

0.9 liter two-stroke engine from. Can handle heavy loads and the AutoCut mowing head can handle even relatively tall bushes and weeds. The D-handle easily adjusts to the height of the operator, so the new owner will be able to adapt the unit completely to himself.

Since the engine displacement is 27.2 cm 3, the Stihl FS 38 trimmer can reach a fairly high speed. The presence of a special quick start system eliminates the need to start the unit several times in a row, because it will start working on the first try.

Specifications and features

  • Mowing width: 23 cm;
  • Fuel tank capacity: 0.33 l;
  • Weight: 4.1 kg;
  • Bar: curved;
  • Line thickness: 2 mm.

Thanks to the manual fuel pump, a person can easily pump fuel into the carburetor. This is especially important in a situation where the mower has been idle for a long time. Constantly adding fuel will allow you to quickly start the device even after a “long vacation”.

For other useful information, see the following document:

The curved bar of the STIHL FS 38 lawn mower with a rounded handle is worthy of attention. Thanks to this design, the device easily copes with the cleaning of the territory, even in narrow or confined spaces.

All controls are located on a comfortable handle, so it takes a long time to look for where and what to switch is not necessary. During work, such a moment is very important, because the operator can not be distracted and adjust the operation of the machine without unnecessary movements.