Frequent malfunctions of Husqvarna 128R grass trimmer

There are many problems that can be solved by adjusting the carburetor. Adjusting the carburetor on your Husqvarna chain saw is necessary if you experience problems such as:

  • Increased idle speed;
  • Strong smokiness when operating the tool;
  • Difficulty starting a cold or hot engine;
  • lack of traction and reduced maximum speed.

This is by no means a complete list of problems that can be solved by adjusting the Husqvarna carburetor. In some cases, adjusting the quality and quantity of the fuel mixture is done after an engine overhaul or during a scheduled maintenance of the chainsaw.

The manufacturer Husqvarna AB recommends adjusting the carburetor before and after the running-in.

Operating principle

The order in which the fuel is pressed and filtered in the lawnmower engine is as follows.

adjusting, carburetor, husqvarna, mower
  • With the help of the throttle valve sets the amount of air supplied to the diffuser. The more air supplied, the more oxygen the gasoline needs to burn, and the more power released in the form of heat. The heat energy is converted into mechanical energy.
  • The diaphragm pump pumps the necessary amount of gasoline.
  • Gasoline then flows through the engine fitting.
  • The fuel flows through the inlet and outlet valves.
  • The fuel is filtered by a strainer.
  • Through the needle valve, it flows into the chamber with a diaphragm.
adjusting, carburetor, husqvarna, mower

The stages of carburetor operation are as follows.

  • Air goes into the air tube with a choke. The choke sets the right amount of airflow.
  • The petrol injection unit has a tapered diffuser in order to increase the airflow rate.
  • Fuel passes through the float chamber and bypasses the nozzle and gets into this narrow tube. The float doses the petrol. In this compartment the pressure is in a state of equilibrium. In the narrowed tube, it goes down. Because of the difference in both pressures gasoline passes through the nozzle.
  • Accelerated flow atomizes gasoline, converting it into aerosol vapor. The resulting gasoline-air mixture is ready to be ignited in the combustion chamber.
  • Passing through the fuel pipe, this mixture ends up in the carburettor cylinder.

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

In the case of buying a Chinese grass trimmer, you should consider that it does not differ much from the European. the same 2 or 4-stroke engine and drive.

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

Make the carburetor adjust

The module configuration is not repairable and replacement is not required. Honda Carburetor Cleaning the carburetor. In this case, a carburetor repair kit for your gas grass trimmer is not required.

  • L. is initially adjustable, as it is responsible for fuel delivery at low speeds;
  • N. Is responsible for gasoline delivery at high speeds, as well as fuel consumption and temperature;
  • T. it is used for easy debugging.

There are variants, usually a Chinese gasoline scraper carburetor, when there is only one screw on the body to adjust. for adjusting the idle speed. This does not mean that the module is automatically adjusted. This means that it will be difficult to perform even this type of repair as a tune-up. The photo shows the adjustment of a Chinese gasoline carburetor.

  • The module is adjusted only when the engine is warmed up: to do this, the device is first turned on for 10 minutes. Adjusting the carburettor If the mower head is idling, start the adjustment immediately: turn the screw T counterclockwise until it stops turning.
  • Adjustment begins with the L screw. Turn the screw left and right until it finds its position at which the idle speed becomes maximum.
  • Then turn the screw and turn it counterclockwise. This will be its working position.
  • The idle action should be adjusted by turning counterclockwise to increase the speed, and clockwise. reduce. Its adjustment is to reach a mode in which enough turns are made before the mower starts to turn. In this case, the engine must work steadily in different positions.
  • The position of screw L is determined by the last. At maximum speeds, the grass trimmer should not run for more than 10 seconds. The throttle opens, the screw rotates clockwise, very slowly, until the rotation speed is reduced to the ear.
  • Then the screw is also turned slowly counterclockwise until the motor fails. Then the screw is turned back clockwise until the engine restarts normally.

We suggest reading Shoes for Extremely Low Temperatures If you have a tonometer and if the product data sheet specifies the recommended speed of rotation, the correction can be made more accurate by focusing on the readings of the device rather than on the ear.

Please explain. In the regulation section of paragraph 5, the L L screw? Should I read screw A? Thank you

Tell me the initial position of the screws H L LA

tell me the initial position of the screws H L LA

Husqvarna 137 Chainsaw Will not Keep Idle RPM

What to do if the chainsaw stalls at idle speed

The chainsaw stalls at idle speed: this is the problem faced by some owners of this tool. The saw is quite light instrument by its construction. The air filter on the fuel filter must be checked before adjusting it. The main problem in troubleshooting is determining the correct cause of the malfunction. Once the cause is established, fixing the defect is usually quite easy.

Probable causes of failure

All chainsaws are powered by a single-cylinder combustion engine. Such malfunctions as disturbance of inner-cylinder compression, change of fuel mixture ratio, incorrect ignition operation, low-quality fuel and lubricants are typical for this type of devices. The main problems in the operation of the power unit are the following:

  • the engine runs steadily at minimum rpm, but stalls when the rpm is increased;
  • starting is normal, but the idle rpm is unstable, quickly stalls;
  • won’t start.

Diagram of chainsaw electronic ignition.

Abnormal operation at idle can be caused by various reasons. They can be divided into several positions:

  • the capacity of the filters (gasoline and air) is reduced;
  • Abnormal operation of the ignition system:
  • the carburetor settings have spontaneously changed;
  • malfunction of gasoline line elements;
  • Clogged exhaust passages, muffler;
  • piston, cylinder, valve defects.

Repair should begin with an external inspection and check for fuel in the tank.

Check and repair of filters

The engine may malfunction or shut down if there is not enough fuel or air. Causes are clogged air or fuel filter. To check the fuel filter, remove the gas line hose from the carburetor nozzle and direct it into a container. Then press several times to pump the fuel. If fuel is pumping normally, in well-defined doses, without dirt, then the fuel filter is serviceable. If the fuel flows weakly or doesn’t flow at all you should replace the filter or if possible clean it.

Sawdust clogging in the fuel filter is one of the reasons chainsaw breaks down.

the device should be removed from the fuel tank (firstly all fuel should be removed). In most models the fuel filter can be pulled out with a wire hook through the neck. If the filter is demountable and can be cleaned, it must be disassembled and washed according to the manufacturer’s recommendations. If not, change for a new filter.

Similar problems can occur if the air filter is clogged with dust, sawdust, or dirt. If there is not enough air the fuel mixture will be enriched, the combustion process will be hindered.

You need to remove the filter to check. When working, you need to take precautions to prevent dust from getting into the carburetor. The device should be cleaned and rinsed in warm water with detergent. If possible, after drying with compressed air at low pressure, put it back in place. If the chainsaw works fine, the cause is fixed, if not, you need to look further.

If you use this tool everyday, it’s a good idea to replace the fuel and air filter every 3 months.

What to do if the chainsaw won’t hold idle speed?

this video you will learn one of the problems the chainsaw has

Runs in low revs and starts.

Husqvarna.Doesn’t work, shuts down.Interesting case

.It doesn’t run well, keeps stalling.I wonder what to do if my chainsaw won’t idle.

Checking the spark plug and ignition system

According to the manufacturers’ recommendations, the spark plug should be changed annually regardless of the intensity of use of the tool. Failure to follow these tips leads to a quite natural result: malfunctions at idle speed, subsequent failure.

Typical ignition system defects are as follows

  • The spark plug is flooded with fuel at startup. It is necessary to remove it from the socket, dry it and if possible blow it out with compressed air. Drain residual fuel from the cylinder through the setting hole, blow out with compressed air. Then install the spark plug, connect the high-voltage cable, start the engine.
  • Lack of spark on the spark plug electrodes. Disconnect the high-voltage wire and check the spark plug. If the spark is normal, check the connection, fix the defects found. Lack of spark on the high-voltage wire indicates ignition unit malfunction. This device is beyond repair, it must be replaced by a new one.
  • The gap between the electrodes is disturbed. This parameter for different types of devices can be within the range from 0,2 to 0,5 mm. Verification and adjustment should be carried out with a special probe or a caliper. Consult the tool operator’s manual for the required dimensions.
  • By the appearance of the spark plug you can determine the direction of the search. If the spark plug is dry after several attempts, it means that there is no petrol in the cylinder. The fuel system and carburettor should be checked.
  • Black soot or carbon deposits on the electrodes could indicate improper carburetor adjustment or a clogged air filter. You may be using bad fuel with a lot of oil. When the ignition system is normal, the electrodes have a uniform gray color and brown deposits on the insulators.

READ Changing a Partner Chainsaw Piston Replacement

Check and repair carburetor

If checking the ignition system, fuel filters, muffler did not give tangible results, the tool still does not want to work properly at minimum rpm, you need to check the carburetor.

To adjust the modes of operation on the body of the device are three screws designed to set the minimum speed of rotation, maximum speed and idle speed.

How to Adjust the Carburetor on a Husqvarna 128r Grass Trimmer

Modern chainsaws have a complex system and consist of several major components, which at times require maintenance and adjustment. Here let’s talk about how to adjust the carburetor on a chain saw Husqvarna.

Hiccups, the solution to which can be adjusted carburetor, enough. Adjusting the carburetor of a Husqvarna chainsaw is necessary if you have such defects as:

  • overrated idle speed;
  • strong smokiness during operation of the tool;
  • Difficulty starting a cool or hot motor;
  • no traction and low maximum rpm.

This is not a complete list of bugs, the solution to which will be to adjust the carburetor Husqvarna. In a number of all kinds of cases, the adjustment of the properties and quantity of fuel consistency is carried out after the overhaul of the engine or during the scheduled maintenance of the chainsaw.

Husqvarna AB manufacturer recommends adjusting carburetor before and after running-in.

To successfully perform a Husqvarna chainsaw carburetor option, you must know its construction and understand how it works. The real thing for our customer is not as difficult as it may seem.

The carburetor has an integrated fuel pump, which is responsible for transporting the consistency of gasoline and oil, and of course the diaphragm, a needle valve with a corona. Their combined work allows to dose the fuel supply into the main chamber and the two flaps.

One of the flaps is designed to regulate the flow of fuel into the cylinder when you press the gas, it is called throttle, another. is responsible for limiting the air supply from the air filter to facilitate starting a cool chain saw Husqvarna.

At the moment when the operator closes the air flow into the carburettor with an air valve, the fuel consistency is depleted and the flow into the cylinder is increased, so that the chainsaw is much easier to start than when a cool start is made in standard mode.

Valve-nozzle is involved in the work of Husqvarna carburetor, which dispenses fuel and prevents the flow of air into the main chamber. It is not uncommon for difficulties during the operation of the saw to be caused by shortcomings of this particular element.

For example, the valve, if the chain saw is not stored properly can stick, the fuel supply will run out, making the work of the motor not feasible. Also, violations in the work of the nozzle will be a prerequisite for sucking air into the main fuel chamber carburetor.

In this case, adjusting the position of the adjusting screws will not fix the situation, it is useful to repair or change the unit.

Three adjustment screws installed in the carburetor body are responsible for adjusting the consistency properties and quantity, and the number of crankshaft revolutions in the idle mode:

  • Screw (L) adjusts the amount of fuel during low and medium speed operation;
  • (H). is responsible for the thrust at high revolutions and their quantity;
  • (T). adjusts throttle valve position to control the amount of fuel consistency entering the cylinder and engine idling.

Screws (L) and (H) cannot be adjusted without some knowledge and experience. Adjustment of wrong quantity and quality of fuel consistency will lead to the fact that the engine will stop working or work incorrectly, leading to its heavy wear or even jamming.

No ordinary slotted screwdriver is good for adjustment. к. The adjusting screws on Husqvarna chain saws have different cross sections. You will have to buy a special, this particular Husqvarna chainsaw repair, they have created what remains for our customer to do, that the saw can be repaired only in the special service Husqvarna.

Husqvarna 125R carburetor adjustment without tachometer (temporary solution)

Husqvarna carburetor is regulated similarly to how the carburetors on chainsaws of other manufacturers are adjusted.

Before the adjustment, you need to make a full diagnosis and make sure that there is no blockage of the fuel and air drain into the crankcase. Also make sure that the air filter is clean and change it for a new one if necessary.

  • The Husqvarna carburetor factory options are installed on the turned off saw.
  • Start the engine and warm up the saw for a few minutes.
  • With the help of turning the screw (L) clockwise, is the position when the engine develops the most speed, after that the screw should be turned back 1⁄4. If in all this the chain of the chain saw rotates, you need to reduce the idle speed, by adjusting the screw (T).
  • The next step is to adjust the power of Husqvarna at the highest rpm and adjust the number of rpm. For this purpose, you connect the tachometer to a running chainsaw, the gas handle is squeezed to the full, then check the tachometer readings. If the value of the maximum rotational speed differs from the maximum recommended by the manufacturer, the tachometer readings are corrected by adjusting the screw (H).

After adjustment the barbed grass trimmer should go up and down and work smoothly in high and low rpm. If the saw chain spins at idle after adjusting the carburetor control screws, it is a sign that the adjustment was done incorrectly and the screw position (T) needs to be corrected.

Also, when adjusting the Husqvarna carburetor, the chain saw’s response time to screw rotation is worth considering. Options do not change overnight, but within 5, 10 seconds.

Huskavrna 128R-repair grass trimmer

One of the characteristics of improperly made adjustments, it is a strong smokiness during the operation of the saw, which indicates a large amount of fuel entering the combustion chamber. If such a situation occurs, it is necessary to correct the position of the propeller (L).

Maintenance, Carburetor. Husqvarna 323RD_x-series Operating Instructions

Warning! The text in this document was recognized automatically. You can use the “Original” mode to view the original page.

This part is manufactured to a specification,

that reduces harmful exhaust fumes. When

engine has consumed 8-10 tanks of fuel, it is considered

“run-in.”. To be sure that the motor

works as it should and that the presence of harmful

exhaust is minimal, bring the machine to your

to the retailer-distributor, for fine-tuning

carburetor. He has the engine rpm counter.

WARNING!Before starting the machine, the clutch cover

A loose clutch can cause injury.

Through the throttle knob, the carburetor adjusts the amount of

engine speed. In a carburetor, there is a

air/fuel mixture. Air/fuel mixture

can be adjusted. To achieve maximum

of the machine effect, the adjustment must be made

Adjusting the carburetor involves

adapting it to the local working conditions,

e.g. to climate, to high altitude, to gasoline and to type 2

Mouthpieces I- and H- are designed to regulate

the amount of fuel by the amount of air that

opens with the throttle knob. By turning the mouthpiece

clockwise, the air/fuel mixture will be leaner

(less fuel), and by turning the nozzles

Counterclockwise, the air/fuel mixture will

richer (more fuel). The leaner the mixture, the higher

will be rpm and the richer the mixture, the lower will be

Adjust the gas level at idle by turning the screw T

rpm. Turning screw T in clockwise direction,

The idle speed will also be higher when turning the screw

counterclockwise, the idle speed will be lower.

When testing the machine in the factory, the following steps are to be carried out

Pre-adjustment of the carburettor. Mixture

is set richer and should remain so in

during the first hours of operation of the machine. then

perform carburetor adjustment. Adjustment

the carburettor must be adjusted by a professional.

If the blades rotate or move when running counterclockwise

at idle speed, the screw T should be turned anticlockwise

Adjustment of the machine’s throttle trigger until the blades stop.

adjusting, carburetor, husqvarna, mower

Recommended idle speed: 2,700 rpm.the maximum recommended amount of

WARNING!If the blades cannot be adjusted

so that the blades are stationary, contact a workshop. Do not

use the machine until the following fine adjustments have been made.

When the machine is “running in”, carry out the following measurements

low rpm I, then idle rpm T and at the end

Before adjusting, check that the air filter is in the correct position

be clean and that there is no cap on it. If

To adjust a carburetor with a dirty air

filter, then the mixture will be poorer, when the filter is cleaned. It can lead to engine failure.

Adjusting the carburetor of a Husqvarna 128R lawn mower.

The first question worth answering in a review of the header topic is Why do you need to adjust the carburetor of a 128 grasshopper mower? it’s all about European fuel standards. the 128R lawnmower is tuned to EU fuel standards. Our fuel is of lower quality (we are talking about gasoline AI-92), which causes the need for this adjustment. The procedure of adjusting the carburetor Husqvarna 128R is not complicated. What you will need to make it. a tachometer of revolutions, adjustment screwdrivers.

We set the length of line out of the trimmer head 15 cm on each side (it significantly affects the speed).

Dilute gasoline AI-92 with Husqvarna engine oil for two-stroke engines in the ratio of 1:50 (one part oil to 50 parts gasoline). For ease of calculation we recommend the ratio of 1 liter of fuel x 20 milliliters of oil. To start the mower for the first time we recommend the ratio of 1 liter fuel x 23 ml oil (the ratio is for the break-in phase of the engine). Maintaining these ratios and using only Husqvarna two-stroke oil is the key to long engine life and warranty fulfillment in case of a warranty claim.

Start the lawn mower and turn the throttle lever to maximum

maximum rpm. Adjust revolutions to 8500 to 8800 on the tachometer with the right adjusting screw H.

Release the throttle grip. At idle speed on top of the carburetor use the T adjusting screw to set the idle speed to 3000-3200 on the tachometer. The engine should run smoothly without jumping. The trimmer head should stop turning.

In case of visible smokiness from the exhaust or unstable idling with the idle speed set. adjust the “quality of the mixture” with the left adjusting screw of the carburetor L.

Having trouble adjusting the carburetor for your Husqvarna 128R lawn mower?. bring it to our service center. we’ll help you.

The practice of Husqvarna gasoline tool service at our service center showed that the need for adjustment occasionally occurs with other models of Husqvarna chain saws and brushcutters as well. These adjustments, by analogy with the method described for adjusting the carburetor of the Husqvarna 128R lawnmower, any user can make their own. Below, by way of reference, we give the engine speed figures for various equipment and in various modes.

From personal experience

Lawn mower or weed trimmer

Lawn trimmers are much more than a lawnmower (mower) because they can also be electric. Gasoline grass trimmer and lawnmower. it is one and the same.

Some authors assure that the grass trimmer. is a weaker tool in contrast to the more powerful lawn mower, which can be used for mowing shrubs. Personally, I have a tool with a maximum power of 1.7 kW and capable, as stated in the manual, to mow small bushes up to 10 mm thick. The owner’s manual is called “petrol grass trimmer. “.

Fuel mixture proportion

I read somewhere that if the manual and the oil can indicate different ratios of the fuel mix, I should use the ratio as indicated in the manual.

For a long time that’s what I did. too much oil was leaking from the engine into the gas tank and the spark plug always had a soot build up on it because the manual showed the ratio for a running-in engine as 1:25, but the canister showed the same ratio. 1:50. After switching to a 1:50 ratio, oil dripping stopped. The spark plug continued to burn, but with less intensity (the carburetor was still out of adjustment).

Until now, some users of gasoline tools determine the proportion of fuel mixture “by eye”. If the mixture will be prepared by underestimating the amount of oil, after a while there may be a strange sound immediately after starting the engine, gradually disappearing during the warm-up, and the engine stops with a sharp jerk. Continued operation of the grass trimmer in this mode will lead to its failure.

Candle Cleaning

In the worst times of trimmer operation with an unadjusted carburetor, the engine would stop starting after using each tank of fuel. And only after cleaning the spark plugs of soot would it be possible to continue working.

Fine sandpaper was used to clean the electrodes, and to clean the space between the insulator and the body. A thin paper clip with a bent end. First, the electrodes were wiped clean with a rag, then sanded with sandpaper. After that the candle was dipped in diesel fuel and the soaked soot scraped off with a paper clip from the surfaces of the insulator, the inside of the body and between them. Next, the candle was dipped several times in the diesel fuel, which was then shaken off with it together with the impurities. Sometimes the procedure of cleaning with a paper clip and flushing was repeated. After that the candle was wiped dry and was ready for further use.

Incredibly, one canister of fuel mixture with an unadjusted carburetor can be used up in less than 10 minutes. tested in practice, when the grass trimmer was started and operated at high revolutions with maximum fuel flow (the adjustment screw was unscrewed much more than the norm).

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