Causes of Damage to Gasoline and Electric Trimmers

The trimmer, both electric and with an internal combustion engine (ICE), is an indispensable tool in the summer and autumn for owners of cottages and private houses. With its help weeds, small bushes are easily removed and the lawn is trimmed. But, like any technique, trimmers fail at the most inopportune moment. To fix the malfunction with your own hands, the user of this technique must first determine the cause of their occurrence.

The main malfunctions of gasoline and electric trimmers

With a gas trimmer and an electric trimmer, if you do not consider breakdowns associated with the barbell and mowing head, malfunctions generally occur in the engine area.

Damage to gas trimmers

Typical breakdowns of the gas trimmer, which are most often encountered by the owners of this unit, are as follows:

  • engine breakdown;
  • problems with the carburetor;
  • fuel supply problems;
  • muffler malfunction;
  • gearbox breakdown;
  • the starter is broken;
  • problems with the air filter;
  • clogged breather on a gas tank.

Causes of Damage to Gasoline and Electric Trimmers

Faulty electrical trimmers

Since the device of the electric mower is much simpler than the mototrimmer, there are few reasons for its failure.

It should be noted that the elimination of some of them is better to entrust to a specialist.

Basically, the trimmer stops working normally in the following cases:

  • malfunction of an electric cable;
  • faulty control button;
  • burned-out motor stator winding;
  • open contact on the engine.

Why doesn’t the gas trimmer start

The reasons why the gas trimmer stopped turning on may be different, therefore, a phased diagnosis of the device is required.

Fuel tank (fuel quality)

Remember that always before starting the unit checking fuel availability and quality. In this case, do not be greedy and save money, as well as “be smart” about the amount of added oil. Everything must be done according to the manual attached to the device, since when the piston group fails, its replacement will cost about 70% of the total cost of the trimmer. Fill fuel with the expectation that you will completely use it up when doing work. The gasoline remaining in the tank loses its properties after a while and can harm the engine. Therefore, do not prepare the mixture for future use and in large quantities. If the brushcutter does not start well, try to drain the “old” fuel from the tank and fill it with a freshly prepared mixture.

Important! Filling the device with fuel whose origin is unknown is fraught with negative consequences. Gasoline must be of high quality, purchased at a gas station, and its brand must not be lower than AI-95.

Candle and candle channel

So, you changed the fuel, but nothing has changed, and the trimmer still does not start. In this case, it is worth checking the candle channel: does it throw it with a combustible mixture. Often users translate air damper to the “OFF” position at startup, and when the engine starts, do not put it in the “ON” position, after which it stalls. Further, an attempt to re-start the ICE leads to the fact that gasoline fills the candle, and the start becomes impossible. To diagnose and resolve a possible problem in this node, do the following:

  1. It is necessary to unscrew the spark plug, wipe it well and dry it. When installing the spark plug in the engine cylinder, it should be dry.
  2. Drain the accumulated fuel from the combustion chamber. This is done through the hole from which you unscrewed the candle.
  3. If there is carbon deposits on the electrodes of the candle, it must be removed either with a thin file or a nail file.
  4. Do not forget to set the gap between its electrodes before replacing the part. The clearance on the candle should be 1 mm. As a probe to check the gap, you can use a coin.
  5. Next, assemble the unit, read the start instructions and try to start the engine again.

If the engine does not start, then you will need to check the spark. For this:

  • unscrew the candle;
  • put a cap on the high-voltage wire on it;
  • touch the metal part of it to the cylinder body (to ensure contact, you can insert a pipe wrench) as shown in the figure below;
  • pull on the start cord so that a few revolutions of the engine occur.

Normally, at each stroke of the piston, a spark should slip between the electrode electrodes. If there is a spark, then the reason that the engine does not start should be sought in other nodes of the device.

For a better understanding of the process, how to test a candle for a spark, you can use this video, where the test is shown on the example of Soyuz petrol scythes.

If there is no spark, then at the beginning check cable, connecting the candle to the coil. perhaps the reason is in it. You can call it using the tester. If an open circuit is detected, a high-voltage wire will need to be replaced.

Also, the reason that the spark disappeared may be ignition coil malfunction (magneto). The figure below shows what the coil (magneto) looks like from the Patriot petrol trimmer.

To eliminate the malfunction, you will need to use a tester to check the magneto trimmer, namely, its primary and secondary windings. On the primary winding, the resistance should be in the range of 0.4 to 2.0 ohms. If the device shows 0, it means that a short circuit has occurred in the winding, and if infinity is a clear sign of an open circuit. The resistance on the secondary winding should be in the range of 6 to 8 kOhm.

On some coils, it can reach 15 kOhm.

Air filter

In the event that your brushcutter does not start well or dies immediately after starting, you should pay attention to the air filter, as it may be clogged, as a result of which air does not enter the combustion chamber and ignition of the fuel does not occur. To check if the filter is in the case, remove it and try to start the engine. If he earned, then the reason is found. The filter needs to be replaced or rinsed well and dried before installation. In case you discovered oil in the air filter, it must be washed with gasoline, squeezed well and dried for at least 2 hours before installing in place.

Video: Causes of Damage to Gasoline and Electric Trimmers

If the unit still does not start when the air filter is removed, it is recommended to check the fuel filter.

Fuel filter

This filter cleans the fuel of possible contaminants. If it is clogged, then gasoline does not enter the cylinder, and, accordingly, the unit does not work or stalls after starting. The fuel filter is located at the end of the intake hose, which is located inside the fuel tank. To get to the filter, you need to remove the plug with the tubes coming out of it.

When removing the plug, the intake hose may disconnect and remain in the tank. It is removed with tweezers.

Next, remove the old fuel filter from the hose and put on it a new one, purchased in advance. Also possible clean the fuel filter, if you don’t have a new one. The filter must be secured to the hose with a spring clip.

Install the intake pipe into the cork and insert the latter into the tank.

It should be noted that in some trimmer models the intake hose is not located on the cork, but inside the tank. You can remove it with tweezers or a hook bent from a wire.


Breather is a check valve, which is designed to equalize the pressure in the gas tank. If it is clogged and does not allow air to flow towards the tank, then a vacuum forms inside the fuel tank and the fuel stops entering the carburetor. To check the serviceability of the valve, remove the hose that goes from the tank to the carburetor. If gas does not flow from the tank, then the breather is clogged.

Users of trimmers often wonder: where is the breather? This valve is usually located in the gas tank cap and looks like the following figure.

Cleaning the breather is very simple: disassemble the valve and flush all its components. In some brush cutters, this valve may be located directly. on the fuel tank. You won’t be able to find it right away, since it is hidden from view under the starter housing. Such a breather is cleaned with a regular needle.

Exhaust channel

The reason that the trimmer has significantly lost power, and when trying to increase the engine speed, it picks them up slowly, is often a clogging of the exhaust channel through which exhaust gases exit the combustion chamber.

It is necessary to remove the muffler so that no burner gets inside the cylinder. Next, clean the exhaust channel of carbon deposits.

This must be done very carefully, preventing carbon deposits from entering the combustion chamber.

After this procedure, the weak power of the unit and the slow set of rotation speed of the mowing head will no longer upset you.

Insufficient compression

If the compression is insufficient, then starting the engine, in most cases, will fail. To check the compression, you can use a car compressor.

  1. Unscrew the candle from the engine cylinder.
  2. Screw the compressometer into its place.
  3. Start yanking the starter cord the way you do when you start the brushcutter. Do this until the arrow on the measuring device stops moving in the direction of increase. This value will also show the compression force of this engine.

What compression should be? Normally, the compression should be not lower than 8 kg / cm 2. Although, even at 8 kg / cm 2, some engines do not have idle and stall, since the fuel is not adequately pumped. If your mower does not pump above 8 kg / cm 2, you will have to check the cylinder, piston and rings.

Poor compression may also be due to loose carburetor. Check if he is staggering. If so, tighten the fasteners that hold it in place. Also, if the carburetor is poorly bolted, you will notice that gasoline is dripping during operation.

Electric trimmer vibrates

Many users of mowers noticed that some time after the device started to work, it begins to vibrate violently. On some trimmers, mainly in more expensive models, an anti-vibration system is installed in the form of shock absorbers located between the engine and the bar. But in some cases even she does not save from strong vibration. The reason that a strong vibration appears in the trimmer may be a small amount or a complete lack of lubrication on a rigid or flexible shaft located inside the apparatus rod.

Replacement hard shaft lubrication happens as follows:

  • unscrew the gearbox located at the bottom of the bar;
  • after removing the gearbox, you will see the end of the shaft, for which you must pull to remove the part;
  • after removing the shaft, it is necessary to grease it with plenty of special lubricant “CV joint-4” or regular. “Litol-24”;
  • apply a small amount of grease to the shaft and evenly lubricate it along the entire length of the part, including the splines at the ends of the rod (if they work together, the shaft will have to be replaced);
  • After lubrication, reinsert the shaft into the rod and put the gearbox back in place.

Flexible shaft lubrication performed as follows:

  • unscrew and remove the mowing head;
  • remove the rod from the electric motor by unscrewing a pair of bolts;
  • pull the flexible cable out of the bar;
  • grease the cable with the entire length.

This is done as follows: first you need to lubricate the end of the cable, and then insert it into the rod, after which, as it moves inside the pipe, lubricate the part and distribute it evenly on the surface. Then insert the shaft with the flexible shaft into the electric motor and secure it.

In case the grease did not help, and the vibration continues to appear, it will be necessary to change the flexible shaft.

The trimmer is very hot

Trimmer overheating can occur for many reasons:

  • gasoline does not have the octane rating indicated in the instructions for the unit;
  • the proportions of gasoline and oil were not observed during the preparation of the fuel mixture;
  • a mixture of fuel with oil was prepared long ago (the mixture cannot be stored for more than 2 weeks);
  • the trimmer works beyond the prescribed time;
  • a low-power trimmer is used on thick and hard grass, the device works with overload and quickly heats up;
  • shifted towards the bar or the cassette lid stuck.

The latter happens if you set mowing head not suitable for this unit, or when the axis is shifted inside the boom. These changes make rotation difficult, the load on the engine increases, and it overheats.