2/1/2022

Stihl F5 38

lawn mowers, like all gasoline powered tools for the garden, are not difficult to maintain. It is possible and necessary to repair, configure yourself. For example, do-it-yourself carburetor adjustment of lawn mowers is a matter of five minutes.

Reuters is committed to unbiased, independent journalism. Accepting funds for advertising or sponsored content allows Reuters to expand our coverage of global news and events consistent with the. Jan 03, 2021 Stihl is best known for its chainsaws, but the company also manufactures string trimmers, and they're among the best on the market. As far as the engine is concerned, gas-powered Stihl trimmers operate on the same principle as chainsaws, the only difference being the connection to the cutting apparatus.

Lawn mowing carburetor is a unit in the power system. In it, like any carburetors, there is a process of mixing air and fuel (gasoline) for further supply to the engine cylinders.

In this process, the main thing is the correct proportion of fuel and air, for which they regulate the carburetor.

The main problems and malfunctions of the carburetor.

Strainer There are only two problems with this element:

  1. Clogging.
  2. Breakage

In order to find out the cause of the breakdown, the fuel filter cover is unscrewed to remove the strainer. If dirt has simply accumulated on it, washing with gasoline or blowing will help.

With visible damage to the strainer, it is imperative to install a new one. There may also be damage on the fuel supply pipe (during repair, check this element).

The carburetor starter in most cases does not function due to blockages. Use rinse with acetone or the same gasoline.

Blowing off carburetor parts with a blockage of compressed air is an acceptable and convenient repair practice.

The throttle body, the bundles of carburetor parts, the intake or exhaust pipe. all of these parts are subject to depressurization. You can probably check it in a primitive way. smear the problem area with soap suds.

The device of the carburetor lawn mowers

Change String In A Stihl F5 38 Weed Eater

The basis of the carburetor of the lawn mowers is an aluminum case. It contains a diffuser (a hole with internal contours). Air is blown through this hole. The oxygen (air) flow rate depends on the cross-section (passage opening) of the diffuser.

The diffuser is equipped with fuel channels. Of these, fuel is drawn in using an air stream.

Outside the carburetor is installed:

  • fuel pump;
  • jet system;
  • fuel / air mixture control system;

How Does Auto Feeder Work On A Stihl F5 38

The principle of the carburetor lawn mowers

Video: Stihl Fs 38 Gas Trimmer Carburetor Adjustment


The throttle valve determines the amount of air for supply, and engine power directly depends on this.

Fuel is sucked into the carburetor system by a pump (its membrane). Then it passes through the fitting in the carburetor. Further, the fluid moves through the inlet and outlet valves of the pump. Filtered by mesh. The needle valve moves into the membrane chamber.

Phased operation of the device:

  1. Air supply to the tube with an air baffle (damper). The partition controls the intensity of the air flow.
  2. The fuel supply system must be narrowed by a diffuser to increase the flow rate.
  3. Gasoline through the float chamber and nozzle tube with narrowing. A camera with a float adjusts the temporary volume of gasoline. In the float chamber, the pressure level is neutral, and in the tube with narrowing is already low. Due to the pressure drop, fuel enters through the nozzle.
  4. The acceleration of the air flow contributes to the transfer of fuel (gasoline) and its atomization. As a result, an air-fuel mixture of the necessary proportion or density is formed.
  5. The air-fuel mixture enters the engine cylinder through the fuel pipe.

The level of air density in the system depends on the area of ​​the open air damper. The wider the flap is open, the greater the fuel consumption and power.

Simply put, adjusting the carburetor on the lawn mower is creating the optimal fuel mixture due to the correct air supply.

How to adjust a carburetor on a lawn mower

Before adjustment, carefully clean the filters according to the maintenance in the instructions.

Do-it-yourself adjustment of the carburetor for lawn mowing is done by adjusting screws. There are three of them:

Right (L). adjustment of the fuel mixture for low revs.

Need to find the maximum idle speed. To do this, slowly turn the screw (L) to the right and left.

To adjust, turn the screw a quarter of a turn necessarily counterclockwise.

Stihl F5 38 Manual

Bottom (T). is responsible for adjusting the engine at idle.

  • clockwise. increase;
  • counterclockwise. decrease.

For proper adjustment of idling, it is typical:

  • steady work of the cold engine;
  • not overestimated speed of the hot engine;
  • a large headroom for the trimmer head;
  • stable operation of the engine when changing position (sharp rise or descent of the knife).

Left (N). adjustment of the mixture at high speeds. (The screw is configured last).

The left-hand screw (N) determines the general adjustment of the maximum speed, engine power, temperature and gas mileage.

Setting the carburetor lawn mowers with the last screw is performed as follows:

  1. Open the throttle to full, while giving out full throttle. Turn the screw clockwise until the speed drops (in this case, they are oriented by ear).
  2. Turn the screw as slowly as possible counterclockwise until the engine runs unevenly.
  3. Then turn back quite a bit, barely hearing a stable, smooth operation.
  4. For a more visual application of skills, it is more convenient to consider the work of an experienced user:

It is interesting that from the point of view of the author of the video, the setting (its correctness) is determined by the color of the candle, and not just by the speed and stability of the engine.

The correct setting of the carburetor with your own hands in this case is the combustion of the fuel mixture without residue, the color of the candle should be light brown.

Related posts:

STIHL FS 38 Grass Trimmer

General

When it comes to getting long grass or wild growth under control, nothing makes it easier than the STIHL grass trimmers. One of the lightest grass trimmer in the STIHL range. Powerful and durable grass trimmer for domestic trimming and lawn edging.

Versions

Price
  • $199.00*

*Prices are valid from the 01/03/2021 to 31/05/2021.
STIHL stores are operated as independent businesses. The products described in this website may not be on display or available at each STIHL store. STIHL reserves the right to change pricing at any time without notice.
The version(s) available in each country may differ from the above range and specifications; specific details may be subject to change without notice. Please ask your local STIHL Approved Dealer for further information.

Technical data

Technical data

Technical dataValue
Standard Cutter Blades AutoCut
Displacement cm³ 27.2
Power output kW 0.65
Weight kg 1) 4.1
Sound pressure level with plastic tool dB(A) 2) 94
Sound power level dB(A) 2) 108
Total length cm 3) 1.470
Cutting tool AutoCut C6-2
Tank volume ml 330

1) Weight excluding fuel, cutting tool and guard
2) K-factor according to DIR 2006/42/EC = 2.5 dB (A)
3) Without cutting tool

The version(s) available in each country may differ from the above range and specifications; specific details may be subject to change without notice. Please ask your local STIHL Approved Dealer for further information.

Features

Standard features

  • Loop handle (R)

    The loop handled grass trimmers and brushcutters are ideal for working in areas where space is limited, e.g. thinning between bushes and shrubs.

  • Multi function handle

    All the engine controls are at your fingertips, allowing easy and safe operation.

The version(s) available in each country may differ from the above range and specifications; specific details may be subject to change without notice. Please ask your local STIHL Approved Dealer for further information.

Accessories

Accessories

    • STIHL VarioClean

      Water based, alkaline detergent specifically for dissolving and removing organic oil residues and for cleaning air filters and housings. The detergent is biodegradable. Avoid contact with the eyes and keep out of reach of children.

    Versions

    Price
    • VarioClean - 500ml --.--**

    *Prices are valid from the 01/03/2021 to 31/05/2021.
    STIHL stores are operated as independent businesses. The products described in this website may not be on display or available at each STIHL store. STIHL reserves the right to change pricing at any time without notice.

    • AutoCut C Mowing Head

      Semi-automatic nylon line head for lawn edging, trimming small areas of grass and around obstacles. Bump and feed operation ensures optimum nylon line length.

    Versions

    Price
    • AutoCut C 6-2 (2.0/2.4) --.--**

    *Prices are valid from the 01/03/2021 to 31/05/2021.
    STIHL stores are operated as independent businesses. The products described in this website may not be on display or available at each STIHL store. STIHL reserves the right to change pricing at any time without notice.

    • Multispray

      Multi function spray that cleans a number of tools and leaves a protective film that does not harden on the surface and thereby protects against corrosion. Rotating parts are lubricated. An essential all-rounder for every workshop. 400ml spray can.

    Versions

    Price
    • Multispray - 400ml --.--**

    *Prices are valid from the 01/03/2021 to 31/05/2021.
    STIHL stores are operated as independent businesses. The products described in this website may not be on display or available at each STIHL store. STIHL reserves the right to change pricing at any time without notice.

    • Harness - Shoulder Strap

      Standard with most STIHL brushcutters, for increased comfort and safety. For FS 38, FS 45, FS 50, HL and HT.

    Versions

    Price
    • Harness - Shoulder Loop $11.80*

    *Prices are valid from the 01/03/2021 to 31/05/2021.
    STIHL stores are operated as independent businesses. The products described in this website may not be on display or available at each STIHL store. STIHL reserves the right to change pricing at any time without notice.

    • Varioclean Special Cleaner

      Multipurpose biodegradable machine and parts cleaner. Water based, biodegradable, alkaline detergent specifically for dissolving and removing organic oil residues and for cleaning air filters and housings.

    Versions

    Price
    • Varioclean - 500ml $17.95*

    *Prices are valid from the 01/03/2021 to 31/05/2021.
    STIHL stores are operated as independent businesses. The products described in this website may not be on display or available at each STIHL store. STIHL reserves the right to change pricing at any time without notice.

    • CF3 Pro Nylon Line

      With CF3 Pro, a high-strength mowing line is realized. The 3 component line is made from high-quality polyamide, increasing the service life of the mowing line. Thanks to the twist, the whistling noise generated when mowing is noticeably quieter. What is more, the new cruciform profile ensures improved mowing performance and neatly trimmed edges. The high-tech mowing line is compatible with many STIHL mowing heads.

    Versions

    Price
    • Nylon Line - CF3 Pro - 2.0mm x 91m $30.00*

    *Prices are valid from the 01/03/2021 to 31/05/2021.
    STIHL stores are operated as independent businesses. The products described in this website may not be on display or available at each STIHL store. STIHL reserves the right to change pricing at any time without notice.

    • CF3 Pro Nylon Line

      With CF3 Pro, a high-strength mowing line is realized. The 3 component line is made from high-quality polyamide, increasing the service life of the mowing line. Thanks to the twist, the whistling noise generated when mowing is noticeably quieter. What is more, the new cruciform profile ensures improved mowing performance and neatly trimmed edges. The high-tech mowing line is compatible with many STIHL mowing heads.

    Versions

    Price
    • Nylon Line - CF3 Pro - 2.0mm x 45m $20.00*

    *Prices are valid from the 01/03/2021 to 31/05/2021.
    STIHL stores are operated as independent businesses. The products described in this website may not be on display or available at each STIHL store. STIHL reserves the right to change pricing at any time without notice.

The version(s) available in each country may differ from the above range and specifications; specific details may be subject to change without notice. Please ask your local STIHL Approved Dealer for further information.

Documents

Stihl F5 38

Owners manuals and safety brochures

LanguagesDateLink
en 29/10/2018