lawnmower does not run at idle speed

Grass trimmer stalls at idle RPM Cause

Grass trimmer, which has a gasoline drive. it is a useful thing for owners of homesteads, lawns, and when the grass trimmer suddenly stops, the work of clearing the area of grass stops. The device itself is a fairly complex mechanism, so there are many different causes of its failure. The most often arising failures are contained in the instruction manual. Knowing the reasons why the grass trimmer stalls should be a good way to effectively repair the device yourself.

Malfunctions with a chain saw associated with the fact that this device does not start are classified in a certain way by service technicians. They highlight malfunctions with the following parts of the mechanism:

  • engine, in which pistons and bearings can wear out or fail, or the crankcase can crack;
  • The fuel system, with a possible clogged filter or problems with the carburetor;
  • mechanical damage to wires, tubes, hoses;
  • the ignition circuit.

In order to correctly determine the node where the failure occurred, it is necessary to pay attention to the circumstances under which the grass trimmer stalls.

READ Lawn Mower Not Starting Causes Video

A gasoline lawn mower does not start a cold

It is not advisable to press the gas when starting a cold engine. Tilt the brush so that the air filter is on top, press the fuel intake button 5-6 times, set the functional lever to the “start” position, pull the starter cord several times to start the engine. After a few seconds of engine operation, turn off the starting system.

Gasoline does not start hot

If the brush cutter has been running recently and is still cold but does not want to start, press the gas trigger, pull the starter cord sharply several times until the engine starts, and only then release the gas trigger. If much time has passed and the brush has cooled, it should be started as if it were cold. If the above methods did not help and the cleaner does not start, contact the service center.

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Gasoline grass trimmer. A useful thing for owners of homestead plots, lawns, and when the grass trimmer suddenly jams, the work of cleaning the site from grass stops. The device itself is a rather complex mechanism, so there are many different causes of its failure. The most common problems are listed in the instruction manual. Know the reasons why grass trimmers kiosk trimmers should be able to effectively repair the unit yourself.

Why the lawn mower stops: causes and solutions

The reason why your tool sharply stops working, namely, the engine revolutions do not pick up, breaks them, or in the popular manner “glows”, there may be more than one. Often not only the engine itself is to blame, but also related systems, units of the unit, completely other parts related to the preparation of the fuel-air mixture, its quality, transportation to the engine tool. Let’s consider the most typical situations:

  • Not picking up revolutions. The mechanics of the engine drive may be damaged or there may be problems with the carburetor, but the main reason is the clogging of the air filter. To improve the situation, it needs to be unclogged, cleaned and if the last one is no longer available it needs to be exchanged for a new one. If the cable from the carburetor is constantly fly off, disassemble the machine and fix it firmly, or buy a new one, if the element is cracked or deformed.
  • At high engine speeds. Cap on the fuel tank is blocked and should be cleaned or replaced. The most common cause is a malfunctioning carb. We give information about the correct adjustment of all screws in the informative articles. Check the quality of the fuel intake hose and replace it with a new one if necessary.
  • When the carburetor heats up. Occurs at moments when the fuel in the carburetor is literally boiling. It can also appear in the variants, if the carb choke is of a more rare, rotary type (not disk type). The only option is to replace the carburetor with a new one. There is also a variant of a punctured wire or ignition coil. In this case change the element last.
  • Starts and stops (right after starting). An unadjusted or misadjusted carburetor is the main cause of this situation. Distinct vibration will indicate an uneven fuel supply, and competent adjustment of the unit will help correct the situation.

We hope you’ve found the right answer to the question: why the lawn mower stops, and all the suggested parts in the catalog today, as always, are at your service. Do you need a piston trimmer for grass, a new carburetor, or related work of these systems. you will find everything on the expanses of the store “Benzo Zip.


All the prerequisites, why the lawnmower does not start, can be systematized according to the specifics of the work of individual nodes. In the service center malfunctions are systematized:

lawnmower, does, idle, speed
  • engine malfunction (worn piston, broken bearing, cracked crankcase);
  • malfunction of fuel consistency supply. clogged pores of the air filter or carburetor malfunction;
  • ignition system doesn’t work;
  • Mechanical malfunction. leaking hoses, broken wires under the braid, broken tubes.

The user should first check whether there is fuel in the tank. Start according to the manual with the saw on its side. Set the air damper in the “closed” position, pump fuel, turn on the ignition and make 3-4 sharp jerks of the starter. STIHL STIHL 250 chain saw stalls on the throttle, throttles on full throttle. If the engine is running, open the air damper. Your STIHL 250 chain saw stalls on the throttle when I press the gas button. The lawnmower does not start. repeat the operations with the air damper slightly open.

At an unsuccessful start, we begin to find the cause of the failure:

  • check the quality of fuel;
  • Check that the spark plug is working properly and that the spark plug passage is clean;
  • Check that the air filter is clean;
  • Make sure the fuel filter is not clogged;
  • check the breather plug for cleanliness;
  • clean the exhaust duct.

complex causes will be, discovered during diagnosis malfunctions that lead to overhaul of the carburetor. Such causes include clogging of carburetor internal passages, wear of the gasket on it and violation of tightness of internal hollows with loss of vacuum. Repairing the lawnmower with your own hands, if it does not start, will require patience.

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Faults of the grass trimmer

The grass trimmer is a convenient and affordable replacement for a lawn mower. Its cutting part is made in the form of a fishing line, knives or a disk installed on a drum, which is closed from above with a protective cover. The basis of the design is the rod, which is adjustable in height, on the end there is a convenient handle and shoulder strap.

As any other technique, the grass trimmer unplanned can break down, and in order that the breakdown did not lead to the final failure of the tool, we suggest you read this article. There are various reasons for the mower malfunctioning. Breakdowns occur both in new trimmers and in those that have been in use for a long time.

Malfunction of electric models

Causes of the sudden shutdown of an electric lawn mower are caused by a broken cord or a lack of power. In the first case it is recommended to check the cable for a breakage. To replace the power cord, you must unplug it from the outlet, open and remove the breaker cover.

Before unscrewing the cable clamp strip? You need to remember the circuit of its connection to the switch. To disconnect the cord use a hexagon socket (1 mm diameter). The clamp is released, the conductors are removed. To check the cable for breakage, a multimeter is used. If necessary, a new cord is installed. The sequence is reversed.

In the second case, it is recommended to connect another appliance to the mains. Electrical apparatus may not work if the fuse in the plug is damaged. To carry out the repair work, it will be necessary to disassemble the plug. A screwdriver and a tester are used for this.

Malfunctions of the motor occur when the lawnmower overheats:

In the first case, wait a few minutes to allow the motor to cool. In the second case, you will need to remove the jammed object. The efficiency of the cooling system depends on the condition of the air filter.

Dirty device has poor air passage, which contributes to the shutdown of the unit. Experts recommend cleaning and changing the filter once every 3 months (if the lawnmower is used continuously).

If the electric motor breaks down, there is a corresponding smell and noise. In this case it is necessary to change the drive.

Engine vibration at idle, on a cold or warm engine: possible causes

Immediately note, there are many reasons for the appearance of ICE vibration, ranging from torn pads (supports) of the engine and ending with ignition skips and thrashing of the power unit. For a more accurate determination, first of all, you should pay attention to one or the other symptoms.

The thing is that the vibration can be constant (regardless of heating and loads on the unit), and manifested in a certain mode of operation (idle or high RPM, when cold or hot). engine vibration may occur when the engine is cold, but as it warms up, it completely disappears. Let’s look into it.

  • For example, if the engine has been recently disassembled for repair (perhaps a complete overhaul), it is very likely that the crankshaft was not properly balanced after re-assembly. The result is runout and increased vibration.
  • Also note that after the repair of the engine to the imbalance and vibrations can lead to different weight, which have details of the cylinder-piston group. The greater the difference in weight, the greater the vibration. For this reason, experienced craftsmen weigh the pistons, pins, etc. before assembly.д.
  • the engine often vibrates when the engine fails to cycle, i.e., one or more cylinders either do not cycle or cycle erratically for some reason. As a rule, the elimination of the cause of the TNT automatically eliminates the vibrations of the propulsion system.
  • Don’t forget that a timing belt or chain aligned incorrectly also causes vibrations.The reason. the engine runs unstable due to the disturbance of the timing of timing.
  • Many engines are fitted with special balancer shafts, which are needed to “dampen” the vibrations. It is quite obvious that problems with these shafts will lead to increased motor vibration.

Engine pads are one of the most common causes of engine vibration. In fact, it is a damper made of rubber on many cars to absorb vibrations. As you know, over time, rubber dries out and cracks, loses its properties as a result of technical fluids, etc.д. The main thing is that the engine with a damaged cushion can not run smoothly.

  • If you have recently switched from one car to another, you should be aware that different engines may have different vibration patterns. The number of cylinders, the layout, and a number of other peculiarities affect the vibration level. In simple terms, a typical inline 6-cylinder engine can run with less vibration than a 4-cylinder and, even more so, a 3-cylinder motor. In this case we are not talking about malfunctions, because for a particular engine a certain level of vibration can be considered the norm.
  • Let us add more to reduce vibration, on the crankshaft of many engines is the so-called torsional vibration damper. If there are problems with the element, the motor will begin to vibrate more strongly.

As you can see, at the initial stage it is important to accurately determine the cause of increased vibration. For example, in most cases, it is enough to replace the engine mount or solve the problem that causes the engine to stall. However, it also happens that the power unit itself needs to be disassembled and repaired.

Repair of mechanical mowers is carried out if the cutting elements are dull or damaged. In this case, experts recommend dismantling the removable blades themselves. For their sharpening an emery is used. If necessary, in battery models, the battery is replaced.

Before repairing the lawnmower, the type of motor is determined:

lawnmower stalls at high engine speeds

The engine speed may drop instead of increasing during operation. Failure of this nature may be caused by:

Fuel hoses on the brushcutter with filter

  • the air is blown into the combustion chamber;
  • problems with fuel mixture circulation;
  • clogging of the breather plug in the fuel tank lid (cleaning the hole with a thin sewing needle);
  • improper carburetor adjustment.

In case of air leakage during internal combustion engine operation it is necessary to check tightness of pipe joints and integrity of gaskets in the cylinder head. The problem with fuel mixture circulation may be solved by the removal of clogging in the fuel pipes leading to the carburetor. If there is a vacuum in the tank and the fuel mixture does not flow to the carburetor, it is sufficient to clean the breather with a fine needle and blow with air.

Why does the injector motor stall?

The direct injection system has a more complex structure than the carburetor system. Therefore, if replacement of sensors does not give results, it is better to apply to a car mechanic. the cause may be insufficient tightness of the intake manifold. At the same time it is necessary to check the vacuum hoses, nozzle sealing rings, gaskets, vacuum booster, manifold plugs. The place of air suction can be easily detected with a smoke gauge. It is sure to be available at the service station. The pressure in the fuel rail should also be checked.

In systems equipped with a pressure regulator, the best indicator is 2.5 atmospheres in idle mode. Systems with a pressure regulator in the tank should have a pressure of about 4 atmospheres. You should also check the ignition system, as well as the spark plugs.

Why the engine does not hold rpm at idle?

If the engine does not hold idle, it does not mean that the machine can not be repaired. Such problem is often encountered by drivers of various car brands, from old “Zhiguli” to modern foreign-made cars. the engine may stutter while idling, for no apparent reason.

Even if the car after that began to work normally, as if nothing ever happened, then such a problem must be solved immediately. There can be a great many reasons for such engine behavior. Let’s consider the main of such causes.

At high revolutions

When the grasshopper stalls at high rpm, it is due to the following malfunctions:

  • clogging or jamming of the valve located on the gas tank lid;
  • The carburetor has become misaligned due to the vibrations produced by the mechanism;
  • problems with fuel mixture circulation;
  • Atmospheric air leakage;
  • The hose intended for fuel intake is cracked or poorly connected.

Adjust the carburetor according to the trimmer’s operating manual. For adjustment it is often enough to loosen the tightening of its body. If there are problems with the circulation of the fuel mixture, it may slowly flow into the carburetor. After it is exhausted, the engine will stall at high rpm.

Recommendations for storing a gasoline grass trimmer in the off-season

When putting the weed trimmer in storage it is worth filling the gearbox with enough oil. Then you need to clean the air filter, partially disassemble, purge and flush the unit’s engine. After drying all mechanisms, you should lubricate the moving elements. To perform oil treatment of the piston system, you must first remove the spark plug. Then you need to move the piston to the extreme position, and then pour a small amount of oil into the spark plug hole and make scrolling of the crankshaft. If you store a gasoline trimmer for grass in the off-season is planned not in the house, it is recommended to wrap the unit’s engine tightly with oiled rags. This will avoid the development of corrosion on the surface of the important nodes of the mechanism.

At idle speed, the following are common causes of grass trimmer stoppage:

  • Reducing the speed of the reducer when it is heated, which is a consequence of using an unsuitable fuel mixture;
  • clogged throttle valve;

If the carburetor is the problem area, the machine will stop on both “cold” and “hot” starts.

Lawn mower malfunctions and how to fix them

any type of chain saw has a hollow shaft, in which a rope is located between the motor shaft and the lower gear that transmits the rotation to the cutting tool. The upper part contains the carburettor and engine, the lower part contains the gearbox and the working tool, closed by the hood. There is a transverse handle in the middle part where the control buttons are located. To unload the hands, there is an unloading belt holding the boom by the operator’s torso.

when selecting a lawn mower, it’s better to have a two-stroke engine than a four-stroke. Two-stroke motor is more maneuverable and easier to repair. The four-stroke engine has a lower vibration level.

It follows that the repair of the lawnmower is to eliminate defects;

  • engine won’t start;
  • the cutting mechanism does not develop;
  • engine stalls;
  • The gearbox heats up;
  • You hear a knocking noise, a powerful rod vibration.

While troubleshooting, it is necessary to carry out diagnosis, to find a non-working node.

It is fundamental to know the lubrication points of the tool. Continuous care, cleaning after work will prolong the life of the machine. Before starting the machine, tighten the mounting bolts, prepare the fuel and fill the tank.

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Electric grass trimmer vibrates

Many mower users have noticed that after a while after starting the machine, it begins to vibrate strongly. Some trimmers, mainly expensive models, have an anti-vibration system in the form of shock absorbers between the engine and the boom. But in some cases even it does not save from strong vibrations. The reason why there is a strong vibration in the trimmer may be a little or no grease on the rigid or flexible shaft, which is located inside the boom of the device.

Lubrication of the hard shaft can be changed as follows:

  • Unscrew the gearbox, which is located at the bottom of the boom;
  • After removing the gearbox, you will see the end of the shaft, which you must pull to remove the part;
  • after removing the shaft, it is necessary to abundantly lubricate it with a special grease “Shrus-4” or ordinary. “Lithol-24”;
  • Apply a small amount of grease to the shaft and spread it evenly over the entire length of the part, including the splines on the ends of the rod (if they worked off, the shaft will have to be replaced);
  • After the greasing, insert the shaft back into the shaft and put it back in its place.

Lubricate the flexible shaft as follows:

  • Unscrew and remove mowing head;
  • Remove the rod from the motor by unscrewing a couple of bolts;
  • Pull the flexible cord out of the rod;
  • Lubricate the entire length of the cable.

This is done as follows: first grease the end of the cable, and then insert it into the rod, then, as you move it inside the tube, apply the grease to the part and distribute it evenly on the surface. Then insert the rod with the flexible shaft into the electric motor and secure it.

If lubrication does not help and vibration continues to be transmitted, the flexible shaft must be replaced.

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Where to start to diagnose the brushcutter

If the lawnmower does not start or immediately stops after starting, it is necessary to check all the main components in sequence. The check algorithm is as follows:

  • Fuel tank (fuel quality);
  • The spark plug and the spark plug passage;
  • Air filter;
  • Fuel filter;
  • Breather;
  • Exhaust port.

These assemblies are most often the source of major problems, which can be corrected after a thorough inspection.

Checking the fuel mixture

Before starting the engine of a gasoline grasshopper, check the presence, and quality of the fuel mixture. Don’t be thrifty, greedy and “smart” in this matter. Repair or replace the piston group will cost you too much (sometimes up to 70% of the cost of a new tool). Prepare the oil-fuel mixture strictly according to the instructions. Calculate its quantity from real needs. Excess gasoline left behind loses its quality over time.

Do a diagnosis of the spark plug and the spark plug duct

If the fuel mixture is of good quality and the mower fails to start, it may be due to a faulty spark plug. A usual spark plug wrench (for sure every motorist has one) and a spare spark plug will do for repair.

  • Unscrew and wipe the spark plug;
  • We dry it thoroughly (it is not necessary to burn it);
  • Drain the excess fuel in the chamber through the spark plug hole and dry it;
  • Clean the old spark plug from carbon deposits with a file or a lady’s file;
  • We expose a gap with a distance of 1 mm (it is possible to check it with any coin);
  • Put everything back and try to start the weed trimmer.

Dry the channel at least 30-40 minutes. Otherwise there is a risk of re-flooding and a new spark plug.

If the spark plug works, its housing is completely dry and the lawnmower won’t start, lubricate the threaded joints with petrol. It should be slightly moistened. No matter how good the spark plug is, there is nothing to ignite in the dry chamber.

If the grass trimmer engine still does not start, you must rule out such a cause as a lack of spark due to poor contact between the spark plugs and the high-voltage wire. If the connection is good, but there is still no spark, most likely, you have a “failed” ignition unit. Here without a master you can not do without, t. к. part is not repairable, but sold as a complete unit.

Lawnmower Filter Diagnosis

Another reason why the gasoline grasshopper stalls can be the air filter. To rule it out, try to remove the filter and start the grass trimmer without it. If it works, then you’ll have to replace the air filter with a new one, or at least blow out and thoroughly clean the old one.

The gasoline grass trimmer may not start because the fuel filter is dirty. This is the next step of our algorithm. Here we check the condition of the filter element and, if necessary, replace it with a new one. When replacing, try not to leave the intake pipe completely without a filter, this is forbidden by any instruction manual. Haste may lead to the repair of the engine piston group.

The breather and the exhaust port

Often “delicate” brand-name models of chain saws don’t start and shut down because of a clogged breather valve. The main function of this element. pressure equalization in the gas tank. When this unit is clogged, a vacuum is created in the tank, preventing the flow of fuel. The problem can be solved by cleaning the breather plug. You can use an ordinary needle for cleaning.

Normal operation of machines with internal combustion engines can be impaired by dirt in the exhaust pipe or a clogged muffler screen. This problem occurs in older models. You can solve the problem with the traditional cleaning and removal of the anti-sparking grid.

complicated reasons of lawn mower failure

If the step-by-step algorithm for troubleshooting has failed, and your grasshopper still does not start or stalls, it is worth inspecting the carburetor and the engine itself. A clogged carburetor may be one of the causes of unstable tool operation. Three main problems can be distinguished here:

  • Clogging of ducts or jets. All this is cleaned with special washes or blown with a powerful jet of compressed air from a compressor. Do not use needles and wire, as the passage sections may be damaged;
  • Wear of the carburetor gasket. The way out is to replace the failed gasket;
  • Difficulty in sealing. An ordinary household tonometer can be used to check this index by replacing the pressure gauge on it with a suitable. Watch the readings: if they do not change. everything is fine, and if the pressure starts to drop, then some part of the carburetor is defective. You have to find it and replace it with a new one.

If everything is okay with the carburetor, the gasoline grass trimmer may not start due to wear of the piston group. If you find chips, scratches or scrapes on the piston or cylinder, replace them. Piston rings must be checked. A slight play of the piston when rocking the crank rod is an indication that it is time to change the rings. This procedure is best left to the professionals at the service center.

When to call a mechanic

If your power tool is under warranty, you may take it to a specialized garage at the first sign of malfunction. Repair is free, regardless of the nature of the damage, if it was not the fault of the owner. If a person who is not technically conversant should get in touch with a specialist at once. In any case, the degree of seriousness of a problem with the machine is determined by the user.

To summarize. Both gasoline and electric trimmers for grass are designed for many years of reliable work. Most of the problems described above, occurs due to the lack of attention of the owner to his assistant. With strict adherence to the manufacturer’s instructions and regular maintenance the lawn mower will run smoothly and without interruptions.

Why does the STIHL electric brush cutter not develop its full power

When using an electric trimmer for grass can also have problems with the speed. Here the reasons are completely different from those for fuel squares.

You can do it yourself

trimmer elektrichesky for grass does not develop the required power, because:

  • The voltage in the mains is more than 10% below the minimum required for the machine;
  • There is a failure in the soft start (if there is such a system);
  • there is a defect in the brush unit;
  • the motor winding has been burned out;
  • Sometimes the rotating parts get stuck.

To get the voltage up and running it’s best to check the output first. If it does not meet the standards, you should increase it with a stabilizer.

The soft starter can only be repaired by an Authorized Service Center.

If the brushes are worn out, simply replace them. When installing new ones, it is recommended to clean all the surfaces with which they come into contact.

To adjust the voltage it is a good idea to check the power first.

If the motor windings are burning up, the electric motor must be replaced.

Jamming of the rotating parts can have various causes. To eliminate them, it is necessary to review the entire drive unit.

The latter problem can also occur with another STIHL pruning shear, and sharpening the blade on the shears is the solution.