Trimmer Does Not Start Well


Trimmer Does Not Start Well

All the reasons why the lawn mower does not start can be classified according to the specifics of the operation of individual units. In the service center, faults are classified:

  • Engine malfunction (piston wear, bearing malfunction, crankcase crack);
  • Malfunction of the fuel mixture supply. Clogged pores of the air filter or carburetor malfunction;
  • The ignition system does not work;
  • Mechanical malfunction. Leaking hoses, broken wires under the braid, ruptured tubes.

The user first needs to check if there is fuel in the tank. Start up in accordance with the instructions with the saw on its side. Set the air damper to the “closed” position, pump up fuel, turn on the ignition and make 3-4 sharp jerks with the starter. If the engine is running, open the air damper. The lawn mower does not start. We repeat the operations with a slightly open air damper.

If the launch fails, we start looking for the reason for the failure:

  • Check fuel quality;
  • Make sure that the candle is working and the candle channel is clean;
  • Check the cleanliness of the air filter;
  • Make sure the fuel filter is not clogged;
  • Check the cleanliness of the breather;
  • Clean the outlet.

complex reasons will be found during the diagnosis of malfunctions leading to overhaul of the carburetor. Such reasons include clogging of the internal channels of the carburetor, wear of the gasket on it and a violation of the tightness of the internal halls with a loss of vacuum. Do-it-yourself lawn mowers repair, if it won’t start, will take patience.

How not to get confused if the lawn mower won’t start

The tool, despite its small size, is a complex technical device. If you study the operating instructions, it turns out that the reasons why the lawn mower does not start are known and removable. It is necessary to consistently eliminate the factors that make it difficult to start the tool. Usually start with more accessible nodes with an easy health check.

Adjustment and tuning of the carburetor

The maximum and minimum engine speed, smooth idle speed are regulated by the carburetor. The stable operation of the lawn mower depends on the amount of the supplied combustible mixture and air, their ratio. The lawn mower will not start if the carburetor is not adjusted correctly. The procedure for adjusting the device for supplying fuel at low speed (L), high speed (H) and idle (T) is regulated by the screws of the same name:

  1. The chainsaw must run for at least 10 minutes, since the adjustment is carried out hot.
  2. Screw H is turned smoothly to maximum speed, then turned by ¼, counterclockwise, reducing the speed of rotation of the engine shaft.
  3. Idling is adjusted with the screw T, ensuring that the scythe does not rotate.
  4. The screw L is adjusted, at first opening the maximum throttle, and then smoothly reducing the speed to stable minimum.

After adjustment, a serviceable carburetor with cleaned filters and a checked ignition must ensure the engine is running. In the event of a carburetor malfunction, after repairing it, you will need to adjust the feed system again before starting the lawn mower.

Rare breakdowns that prevent lawn mowers from working can be:

  • Rewind spring failure;
  • Broken or stuck starter pulley;
  • Faulty starter assembly.

The most important malfunction, the elimination of which is associated with replacing the engine, may be the failure of the engine piston group. The cost of repairs will cost about 70% of the cost of the product. Understanding the reasons why the lawn mower won’t start will help:

Eliminating the reasons why the lawn mower won’t start

The fuel mixture must be prepared with the exact proportions of gasoline and oil. In this case, you cannot use another brand of fuel. To exclude the ingress of dirt, gasoline should settle in glass or metal containers for 2 days. Do not use plastic utensils for storing fuel. Measure oil accurately with a medical syringe without a needle. Use only freshly prepared mixture, do not leave unused fuel in the tank. If the engine is naughty, the lawn mower stalls, when you press the gas, the fuel may be to blame.

Checking the ignition system, if the lawn mower does not start, is carried out sequentially:

  • Clean the removed candle from carbon and dirt, dry it, set a gap of 1 mm;
  • Connect to a high-voltage wire and check for a spark by pulling the starter several times;
  • In the absence of a spark, check the high-voltage wire for integrity;
  • Replace the candle;
  • Dry the candle channel;
  • At the same time the operation of the ignition coil is checked, it is faulty if the working plug does not spark.
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It is in the event of a malfunction of the ignition coil of the lawn mower does not start up hot, stalls, works intermittently.

Cleaning or replacing the air and fuel filter will ensure the proper consumption of ingredients entering the carburetor. The air filter can be washed in soapy water or replaced. If nylon fabric is used, it is washed, the porous felt filler is replaced. Change the fuel filter carefully without leaving the intake manifold open. Whether it is necessary to replace the air filter can be determined if the engine starts with the air cleaner removed. Do I need to change the grid on the fuel supply if the lawn mower does not start, a dry candle will tell.

Breather, gas tank air inlet. If it gets clogged, a vacuum is created in the tank and the mixture does not enter the carburetor. The hole can be blown out with air or cleaned with a needle. Clean the exhaust duct, remove the anti-spark screen of the muffler.

Taking proper care of your chainsaw

There are no unnecessary phrases in the operating instructions, everything that is offered is aimed at trouble-free operation of the lawn mowers. Cleaning all parts after each work cycle facilitates the easy removal of uncured residues and dirt. Only the cooled nodes need to be cleaned. This technique contributes to the quality of air cooling of the engine and gearbox.

For refueling, you must use fuel with the oil recommended in the instructions. If the combustible mixture is left in the fuel tank, the oil will float up and, when started, will land on the damper, impairing its adjustment. The mixture can sediment and clog the fuel feed in the carburetor.

It is impossible, it is dangerous for the tool and the health of the mower, to use a metal cable instead of a fishing line. It cuts more efficiently, but the load on the gearbox and engine increases. A worn-out piece of wire, when it comes off, flies at the speed of a bullet. Effective mowing can lead to early wear of the engine piston group. For more efficient mowing, it is suggested to use the “star” line profile.

Trimmer won’t start

Like any technique, trimmers are subject to various breakdowns. Often at the beginning of the summer cottage, the owners of such a tool complain that the trimmer does not start, and it takes a long time to look for the cause of the malfunction.

For those who have recently purchased a trimmer and are still “you” with this technique, it will be useful to know why the trimmer does not start and what to do in this case. So let’s find out what may be causing this.

Petrol trimmer won’t start. 10 possible reasons

Before attempting to adjust the operation of the tool yourself, carefully study the manual for its operation. Perhaps the information contained in it will push you to this or that thought. Otherwise, you will have to look for the cause of the malfunction by the selection method. It can be one of the following:

  1. The toggle switch on the boom is not in the “On” position. This is one of the basic steps, but sometimes beginners forget to turn on the tool before launching it.
  2. Lack of fuel in the tank also belongs to such errors. If you run out of fuel and you forgot about it, just fill the tank (usually located near the engine) with AI-92 gasoline.
  3. Lack, improper mixture or incorrect proportion of engine oil. Ideally, no more than 50 g of oil should be added regularly. This will provide additional lubrication and keep your trimmer motor running. Also keep in mind that there are different types of oil (“synthetics”, “semisynthetics”, “mineral water”). They all have a different effect on the operation of the mechanism.
  4. If the trimmer mower does not start after winter, drain the remaining fuel in the gas tank and replace it with fresh fuel. This is especially true for small, low power trimmers with small motors that are sensitive to poor quality mix. In addition, during the winter, sediment can form at the bottom of the gas tank, due to which problems arise with the operation of the device.
  5. Excessive pumping of fuel can also be one of the reasons that the trimmer stalled and will not start. When the choke is closed, the spark plug is flooded with fuel. It should be unscrewed and dried, and then inserted into its place and try to start the engine while holding the gas trigger. It is advisable to check it before that there is a spark between the electrodes. If there is no spark, the candle should be replaced.
  6. Filter problems. If your trimmer does not start well, remove the air filter and start the tool without it. If everything worked out, the filter should be replaced with a new one. As an option. Thoroughly clean and blow out the old one, however, sooner or later you will have to make a replacement.
  7. Trimmer stalled and won’t start? Try to clean the so-called breather. An element designed to equalize the pressure in the gas tank. Cleaning can be done with a regular long needle. A clogged breather often causes a malfunction.
  8. The knives have been removed from the machine. Some models will not work under this condition.
  9. Violation of tightness. You can check this with a pressure gauge. If the pressure starts to drop, you should determine which of the parts of the carburetor is faulty. Most often the carburetor gasket wears out.
  10. Sometimes, after a long period of operation, you will notice that the trimmer is overheated and will not start. First, you should know to take breaks. The amount of continuous operation time recommended for this model should be indicated in the instructions. Also, the problem of overheating may lie in a faulty ignition coil or in the air cooling system, which prevents overheating.
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If none of these actions worked, you should contact a repair shop or service center.

Malfunctioning electrical trimmers

Since the device of an electric mower is much simpler than a motor trimmer, there are few reasons for its failure.

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

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

  • Electrical cable malfunction;
  • The control button is faulty;
  • Burned out motor stator winding;
  • Breakage of contact connections on the engine.


The breather is a non-return valve designed to equalize the pressure in the gas tank. If it is clogged and does not allow air to pass towards the tank, then a vacuum is formed inside the fuel container, and the fuel stops flowing into the carburetor. To check if the valve is working, remove the hose that goes from the reservoir to the carburetor. If gasoline does not flow out of the tank, then the breather is clogged.

Trimmer users often ask themselves: Where is the breather? This valve is usually located in the gas cap and looks like the following figure.

Cleaning the breather is very simple: disassemble the valve and rinse all of its components. On some mowers, this valve may be located directly on the fuel tank. It will not be possible to find it right away, since it is hidden from view under the starter housing. Such a breather is cleaned with a regular needle.

Trimmer won’t start

Like any technique, trimmers are subject to various breakdowns. Often at the beginning of the summer cottage, the owners of such a tool complain that the trimmer does not start, and it takes a long time to look for the cause of the malfunction.

For those who have recently purchased a trimmer and are still “you” with this technique, it will be useful to know why the trimmer does not start and what to do in this case. So let’s find out what may be causing this.

The trimmer gets very hot

Trimmer overheating can occur for many reasons:

  • Gasoline has the wrong octane number, which is indicated in the instructions for the unit;
  • The proportions of gasoline and oil were not observed during preparation of the fuel mixture;
  • The mixture of fuel and oil has been prepared for a long time (the mixture cannot be stored for more than 2 weeks);
  • The trimmer works beyond the time prescribed by the instructions;
  • A low-power trimmer is used on thick and hard grass, the device works with overload and heats up quickly;
  • Shifted towards the boom or stuck on the cassette cover.
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The latter happens when an unsuitable mowing head is installed for the machine, or when the axle moves into the boom. These changes make rotation more difficult, the load on the motor increases, and it overheats.

The main malfunctions of the trimmers: does not start, vibrates strongly, heats up during operation

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

Candle and candle channel

So you changed the fuel, but nothing has changed, and the trimmer still won’t start. In this case, it is worth checking the candle channel: does it cover it with a combustible mixture. Often, users turn the choke to the “OFF” position at start-up, and when the engine starts, they do not turn it to the “ON” position, after which it stalls. Further, an attempt to restart the internal combustion engine leads to the fact that gasoline fills the candle, and the start becomes impossible. To diagnose and fix 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 into the internal combustion engine cylinder, it must be dry.
  2. Drain the accumulated fuel from the combustion chamber. This is done through the hole from which you unscrew the candle.
  3. If there is carbon deposits on the electrodes of the candle, it must be removed either with a thin file or with a nail file.
  4. Do not forget to set the gap between its electrodes before installing the part. The gap on the spark plug should be 1 mm. You can use a coin as a probe to check the gap.
  5. Next, reassemble the unit, read the starting instructions and try to start the engine again.

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

  • Unscrew the candle;
  • Put the cap of the high-voltage wire on it;
  • Touch its metal part to the cylinder body (to ensure contact, you can insert a pipe wrench) as shown in the figure below;
  • Pull the starter cord until the engine rotates a few times.

Normally, every time the piston moves between the electrodes of the plug, a spark should slip. If there is a spark, then the reason that the internal combustion engine does not start should be looked for in other nodes of the device.

For a better understanding of the process, how to test a spark plug, you can use this, where the test is shown on the example of the Soyuz lawn mowers.

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

Also, the reason for the missing spark may be a malfunction of the ignition coil (magneto). The picture below shows what the coil (magneto) looks like from a Patriot petrol trimmer (Patriot).

To exclude a malfunction, you will need to check the trimmer magneto with a tester, namely, its primary and secondary windings. On the primary winding, the resistance should be between 0.4 and 2.0 ohms. If the device shows 0, this 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 must be between 6 and 8 kΩ.

On some coils, it can reach 15 kΩ.