Why Gasoline Doesn’t Come To The Trimmer

Caring for a personal plot, summer residents periodically encounter the fact that the lawn mowing does not start. There are many reasons for tool failure. For the correct diagnosis of the problem, the owner of the unit useful at the cottage needs to know the device and the principle of operation of its individual parts.

Why Gasoline Doesn’t Come To The Trimmer

  • Where to start diagnosing lawn mowers
  • Checking the fuel mixture
  • We diagnose a candle and a candle channel
  • Diagnostics of lawn mowing filters
  • Breather and exhaust channel
  • More complex causes of lawn mowing failure
  • Rules for the operation and storage of lawn mowers

Where to start diagnosing lawn mowers

If the lawn mowing does not start or immediately stalls after start-up, it is necessary to check all the main components and assemblies in sequence. The verification algorithm is as follows:

  • Fuel tank (fuel quality);
  • Candle and candle channel;
  • Air filter;
  • Fuel filter;
  • Breather;
  • Exhaust channel.

These nodes are most often the source of major problems that can be fixed after a thorough inspection.

Checking the fuel mixture

Before starting the engine of the gas spit, check the availability and quality of the fuel mixture. Do not save, do not be greedy and do not be clever in this matter. Repair or replacement of the piston group will cost you too much (sometimes up to 70% of the cost of a new tool). It is necessary to prepare the oil-fuel mixture strictly according to the instructions. Calculate its quantity from real needs. Excess gasoline remaining after work over time loses its quality.

We diagnose a candle and a candle channel

If the quality of the fuel mixture is not in doubt, and the lawn mower stalls at start-up, then a filled candle may become the cause. Here, for repair, an ordinary candle key (probably every motorist has it) and a spare candle are suitable.

  • We twist the candle and wipe it;
  • Dry it thoroughly (do not calcine);
  • The excess fuel in the chamber is drained through the spark plug hole and dried;
  • We clear an old candle from a deposit by means of a file or a lady’s file;
  • We set a gap with a distance of 1 mm (you can check with any coin);
  • We return everything to its place and try to start a trimmer.

If the candle is working, the nest where it is completely dry and the lawn mower does not want to start, we lubricate the threaded connection with gasoline. It should be slightly moistened. No matter how wonderful a spark a candle gives out, there is simply nothing to light up in a dry chamber.

If the trimmer motor still does not start, a cause such as the absence of a spark due to poor contact between the spark plugs and the high-voltage wire should be excluded. If the connection is high-quality, but there is still no spark, most likely, your ignition unit has “flown”. Here you can’t do without a master, because the part is not being repaired, but sold as a single unit.

Diagnostics of lawn mowing filters

Another reason that the gas braid stalls may be an air filter. To exclude it, try to remove the filter and start the trimmer without it. If possible, then you will have to change the air filter to a new one, or at least blow out and thoroughly clean the old one.

A gas trimmer may not start up due to contamination of the fuel filter. This is the next step in 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 suction pipe completely without a filter, this is prohibited by any operating instructions. Haste can result in repair of the engine piston group.

Breather and exhaust channel

Often, "gentle" branded lawn mowers do not start and stall due to contamination of the breather. The main function of this element is to equalize the pressure in the gas tank. If this unit becomes clogged, a vacuum is created in the tank, which prevents the fuel supply. You can fix the problem by cleaning the breather. You can use a regular needle for cleaning.

Normal operation of the braids with internal combustion engines may be impaired due to the ingress of dirt into the exhaust channel or clogging of the silencer mesh. There is such a problem on older models. You can solve the problem by traditional cleaning and removal of the anti-spark mesh.

More complex causes of lawn mowing failure

If the step-by-step algorithm for troubleshooting does not give a result, and your braid still does not start or stalls, it is worth examining the carburetor and the engine itself. A clogged carburetor can be one of the reasons for unstable tool operation. Three main problems can be distinguished here:

  • Clogged channels or jets. All this is cleaned with special washes or purged with a powerful jet of compressed air from the compressor. Do not use needles and wire, as passage sections may be damaged;
  • Worn carburetor gasket. Output – replacement of failed gaskets;
  • Violation of tightness. To check this indicator, you can use an ordinary household tonometer, replacing a manometer with a suitable one. Keep track of the readings: if they do not change, everything is fine, and if the pressure starts to fall, then some part of the carburetor is faulty. We’ll have to find it and replace it with a new one.

If everything is in order with the carburetor, then the gas trimmer may not start due to wear on the piston group. If chips, scratches, or nicks are found on the piston or cylinder, they should be replaced. Piston rings are subject to mandatory inspection. A slight piston loophole while rocking the connecting rod indicates that it is time to change the rings. This procedure is best entrusted to service center specialists.

Rules for the operation and storage of lawn mowers

In order for the lawn mowing to continue well, you need to provide it with good storage and operating conditions:

  • During operation, carefully monitor the cooling system, carefully and timely clean the channels in the housing, as well as the fins of the starter;
  • If necessary, use solvents, kerosene and other detergents for cleaning;
  • Do not clean the tool “hot” – let it cool;
  • Strictly follow the requirements of the instruction regarding the operating mode, otherwise you may overheat the engine;
  • If you do not plan to use the lawn mower in the next month, the fuel mixture must be drained from it, because over time it breaks up into heavy fractions that will uniquely clog the carburetor channels;
  • After draining the fuel, let the trimmer idle until it dies, this will help to completely remove the remains of the working mixture.

Before winter storage, follow these steps:

  • Completely disassemble the braid, rinse and clean all the details that you can;
  • Inspect the parts for damage, if necessary, eliminate distortions, gusts, bends and any other malfunctions;
  • Pour enough oil into the gearbox and clean the air filter;
  • You can partially disassemble the motor, flush, blow and grease all moving parts;
  • In order to lubricate the piston, you need to unscrew the candle, raise the piston to the dead center with the starter, pour a little oil into the spark plug hole and rotate the crankshaft a couple of times;
  • If you are not keeping the lawn mowing house, wind the engine with an oiled rag.

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.

Video: Why Gasoline Doesn’t Come To The Trimmer

The main malfunctions of gasoline and electric trimmers

For lawn mowers and an electric trimmer, if we do not consider breakdowns associated with the boom 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.

Faulty electrical trimmers

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

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 lawn mowing does not start well, try to drain the “old” fuel from the tank, and fill it with a freshly prepared mixture.

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.

To better understand the process of how to test a candle for a spark, you can use this video, where the test is shown on the example of the Soyuz lawn mowers.

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 can serve as ignition coil malfunction (magneto). The figure below shows what the coil (magneto) looks like from the Patriot (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.

Air filter

In the event that your lawn mower starts poorly or dies immediately after start-up, 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.

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.


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 lawn mowers, 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.

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 lawn mowing. 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 lawnmower does not swing 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 this way: 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.

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.