Why the lawn mower and trimmer won’t start: possible causes and solutions

If the trimmer or lawn mower does not start, then any desire to mow the grass disappears. Very often, owners of these tools encounter difficulties starting a two-stroke or four-stroke engine after winter, when the tool has not been used for a long time. If such a situation occurs, then you should not rush to return the instrument for repair. Start troubleshooting from least to most, and with 100% probability you will be able to start the gas trimmer engine. Let’s look at where to start troubleshooting when the lawn mower won’t start, step by step with all the details.

The trimmer won't start - what components need to be checked?

To start gasoline trimmers, manual starters are used. These starters are used to manually move the crankshaft. In this case, it is important to turn on the ignition so that when the crankshaft rotates, the fuel-air mixture entering the cylinder can ignite. Ignition of the first portion of the mixture will cause the engine to start, and the trimmer is ready for use.

However, it very often happens that attempts to start the engine are frustrated. Naturally, when after 5 attempts to start the engine you cannot achieve success, then you need to start diagnostic measures. There is a special sequence that should be followed in order to find the reason why the lawn mower does not start and successfully eliminate it. The check sequence has the following format:

Check the presence of fuel in the tank, as well as the quality of the mixture of gasoline and oil
Determine the color of the spark plug, as well as signs of its functioning
Make sure the air filter is working properly
Check the fuel filter, which is responsible for cleaning gasoline and oil entering the carburetor
Breather serviceability
The reason why the lawn mower does not start may be the exhaust duct or the muffler.

It is these nodes that are the main sources of the problem of difficult starting of the trimmer. A more complex problem involves a faulty carburetor that needs adjustment. Let's look at each unit separately to find out the reasons why the trimmer does not start and fix them with your own hands.

Troubleshooting

All the reasons why a lawn mower does not start can be classified according to the specific operation of individual components. The service center classifies faults as follows:

engine malfunction (piston wear, bearing failure, crankcase crack);
malfunction of the fuel mixture supply - clogged air filter pores or carburetor malfunction;
The ignition system does not work;
mechanical failure - leaking hoses, broken wires under the braid, rupture of tubes.

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

The brush cutter cannot work for a long time. The gearbox and motor will overheat. You can mow for no more than 15=20 minutes, taking a five-minute break. On a hot afternoon, the operating time is halved. When mowing weeds and sedges, the work time must be reduced.

If the launch fails, we begin to look for the cause of the failure:

check the quality of the fuel;
make sure the spark plug is working and the spark plug channel is clean;
check the cleanliness of the air filter;
make sure that the fuel filter is not clogged;
check the cleanliness of the breather;
clean the exhaust channel.

More complex reasons will be those detected during diagnostics of a malfunction, leading to a major 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 loss of vacuum. Repairing a lawn mower yourself if it won't start will require patience.

The first step is to check the availability and quality of fuel

If you don’t understand why the lawn mower won’t start, then first make sure that there is fuel in the tank. Beginners often forget that they need to pause periodically to fill the tool with a gasoline-oil mixture. If the gas mower's tank is empty, then naturally it will not start, no matter how much you try to do it.

If there is fuel in the tank, but it is impossible to start the engine of the tool, then do not rush to disassemble the carburetor. Make sure that the trimmer motor is started correctly as indicated in the instructions. If the launch is carried out according to the instructions, then it is important to consider the following points:

Use not just high-quality gasoline with the maximum octane number, but exactly the brand recommended by the manufacturer. And this brand is not always AI-95 gasoline. If you don’t know what gasoline to use for your lawn mower, then choose AI-92
The oil must be special - for two-stroke engines. If the lawn mower has a four-stroke engine, then you need to fill it with pure gasoline without mixing it with oil. You should not skimp on the quality of trimmer engine oil, just like you should not skimp on gasoline. After all, the service life of the engine depends on the quality of the fuel used.
Proper preparation of the fuel mixture in the gas trimmer. Observations show that most mowers control the process of preparing oil and gasoline for the trimmer only at first. The more experienced the mower, the less attention is paid to the process of mixing gasoline with oil for a two-stroke engine. The ratio of gasoline to oil should be as recommended by the manufacturer. Usually this ratio is 25 to 1, that is, for 1 liter of gasoline you need 40 ml of two-stroke oil (motor oil for a car, much less used oil, cannot be used)
Proper storage of the fuel mixture. It often happens that after preparing the fuel mixture, it sits for a long time, more than 2 weeks. It is impossible to store a ready-made mixture of gasoline and oil for a long time, as this leads to the fact that the oil precipitates, and thereby the properties of both petroleum products are lost. Even thorough stirring after long-term storage of the finished mixture is not a reason for its further use. That is why it is not recommended to prepare more than 2 liters of mixture at a time.

Make sure that all of the above points have been completed, and only then can you start checking the condition of the spark plug. The trimmer does not start for various reasons, and most of them can be identified independently. It is simply irrational to resort to disassembling the carburetor if it is impossible to start the engine. The next step towards troubleshooting is checking the condition of the spark plug.

This is interesting!
During long-term storage of diluted gasoline with oil, these elements decompose into heavy fractions. These fractions clog not only the instrument’s fuel filter, but also the carburetor channels. The maximum duration of fuel storage is no more than 14 days.

What to do if the gas trimmer does not start

A long seasonal break in work, violation of storage rules and non-compliance with operating standards, lack of constant maintenance lead to the fact that the gas trimmer does not start. Then the first thing you need to do is make sure of the assortment of the fuel mixture and its quality.

For gasoline trimmers from manufacturers such as Stihl or Husqvarna, it is necessary to prepare the oil-fuel mixture according to the indicated instructions using oil of the corresponding brands. After making sure that the fuel mixture is perfect, but the tool still does not start, make sure that you have an assortment of sparks, which may often be missing due to a flooded spark plug. If the spark plug is dry, the connection is good, but there is no spark, most likely the ignition unit has failed.

What to do if the above points are in order, no matter how annoying it may sound, the Sturm lawn mower or the Stihl gas trimmer does not start? It is necessary to diagnose the gasoline and fuel filters, and also carefully examine the carburetor for possible wear of the piston group.

Dry and wet spark plug, what does this mean and how does it affect engine starting?

Most tool owners immediately resort to checking the condition of the spark plug contacts. This is done in order to understand from the condition of the spark plug what could be the reason for the impossibility of starting the lawn mower engine. Based on the condition of the spark plug contacts, appropriate conclusions can be drawn about what may be causing the malfunction. Diagnosis of the spark plug on the trimmer is performed in the following order:

The spark plug is unscrewed, after which it is subject to inspection. The ideal condition of the electrodes is if they have a brown soot (brick color). If the spark plug is wet and has black or white carbon deposits, this indicates a corresponding malfunction
If the spark plug is wet, then there is a portion of unburnt fuel in the combustion chamber that does not need to be drained. Clean and dry the spark plug contacts, then make sure it is in good condition. To do this, connect it to the candle holder and place it on the surface of the cylinder. Turn on the ignition and pull the starter handle lightly. In this case, the spark plug should produce a high-quality and constant spark. If the spark is weak or absent at all, then the spark plug should be replaced.
The trimmer may not start due to a large gap between the spark plug contacts. The gap between the spark plug electrodes should be in the range from 0.7 to 1 mm. To set the gap, special feeler gauges are used

This is interesting!
Drying spark plug contacts by calcining them is strictly contraindicated, as this method will lead to damage to the part.
If there is a spark at the spark plug, but the trimmer does not start, then the reason lies in the supply of the fuel mixture to the combustion chamber. To make sure of this, you should do the following:

Take 20 grams of fuel into the cap of a PET bottle or into a syringe
Pour it into the combustion chamber through the spark plug hole
Screw in the spark plug
Put on the candle holder and start the engine

If the engine of the lawn mower starts after the above steps, then the cause of the malfunction should be sought directly in the fuel line and carburetor. If the engine does not start even after these steps, then you need to check the serviceability of the high-voltage wire. The high-voltage wire, like the spark plug, is a consumable item. If there is a suspicion that the trimmer's armored wire is faulty, it should be replaced. If, after the above steps, you cannot start the engine of the lawn mower, then you need to take into account the following recommendations:

If there is any doubt about the serviceability of the spark plug and high-voltage wire, it is recommended to replace them immediately
Check that sparking is working properly, and if there is no spark on the new spark plug, then the breakdown is related to the ignition unit - coil failure
The ignition coil is not repaired, but replaced. If the diagnostics really indicate a malfunction of the lawn mower’s ignition coil, then it is not difficult to replace it with your own hands

If there is a spark plug, and it is dry, and the trimmer does not want to start, then we move on to checking the next unit - the air and fuel filters.

This is interesting!
If the spark plug electrodes are red or pink, this indicates that the fuel used contains a large amount of additives. You should refuse such fuel by changing the gas station or brand of gasoline.

Main reasons

Experience shows that gasoline trimmers stop starting or working normally after winter, in other words, long seasonal storage. Before subsequent attempts to start the tool, you should conduct a thorough diagnosis with the goal of determining the source of the problems. At the moment, there are several more common malfunction events.

First you need to check the quality of the fuel. Saving in such cases has very bad consequences. Experienced owners of lawn mowers and specialists advise preparing a mixture in the amount required to correspond to future work, because its excess quickly loses its characteristics.
Trimmers of such famous brands as, for example, Husgvarna, Makita, Stihl, are very sensitive to the fuel used. We are talking about fuel quality and octane number. Refueling with high-quality gasoline will ensure suitable operating conditions and extend the service life of equipment.
At the moment of starting, the engine of the lawn mower may stall due to the spark plug being flooded. Often in such situations one has to deal with the need for a carburetor function. It is worth noting that such problems arise when the scythe stops starting when hot.
At times the tool fails to start, although the spark plug is wet, which then indicates that the fuel mixture has entered the combustion chamber. As a rule, this is one of the symptoms that there is no spark. The reasons include the lack of normal contact between the spark plugs and the high-voltage wire or the drying out of the threaded connection in the spark plug channel.
If there are no difficulties with the spark, and yet the spark plug itself remains dry, then this almost always indicates that gasoline is not being pumped. There are several events that will happen to you under these circumstances. We are talking, directly, about the condition of the fuel filter and carburetor.
The scythe's internal combustion engine does not start or immediately after starting it stops working, which may be due to a clogged air filter, which prevents the normal supply of air suitable for enriching the mixture.

Apart from all of the above, trimmer owners have to deal with more severe troubles. One of these is wear of the piston group. In this option, entrust it to professionals, which will significantly reduce costs and extend the life of the tool.

If the trimmer does not start, check the serviceability of the filters

You will need to check the air filter, which cleans the air entering the carburetor. Clogging of the cleaning element leads to the fact that air enters in less quantity or completely stops supplying it to the carburetor. You can find out whether the air filter is the reason why the trimmer does not start in a simple way:

Remove the air filter and inspect it. The presence of blockages is already a reason to blame this part for everything
If clogging is not visually detected, then you need to try to start the engine without a filter. If the trimmer starts without a filter, then this part definitely needs to be replaced.
The air filter can be cleaned with a stream of compressed air, but if it has not been changed for a long time, then it is advisable to replace it with a new one

It should be noted that the trimmer may not start due to a clogged air filter, but these are extremely rare cases. Often, a clogged air filter affects the stability of the engine and also contributes to a decrease in performance.

This is interesting!
If the chainsaw starts up without an air filter, then working with the tool without a filter element is contraindicated, since contaminants will get into the cylinder, thereby reducing the service life.
The real reason why a gasoline trimmer won't start is that the fuel filter is clogged. This part is located in the tool tank, and if the scythe is more than 2 years old, then it’s time to check the serviceability of the fuel filter element. If the filter is clogged, then the fuel mixture will not flow into the carburetor, which means the trimmer will not start.

There are no difficulties with replacing the fuel filter, since to do this it is enough to remove this part from the tank and replace it. If you are going to clean the fuel filter with a compressor, then it is recommended to abandon this idea. It is better to buy a new filter for cleaning the fuel of a lawn mower, since there will still be blockages inside the old element. The video below shows the process of replacing the fuel filter on an Oleo-Mac brand lawn mower.

If you are not sure that the reason why the trimmer motor cannot start is the fuel cleaning element, then you should do the following:

Remove the fuel filter
Start the lawn mower
If it starts, and quickly, then the problem is really in the fuel filter.

The filter becomes clogged due to the following reasons:

During prolonged use of the tool
If low-quality gasoline or oil is used
When storing fuel in the tool tank for a long time
If you fill the tank with fuel that has been stored for a long time
If dust and small particles get into the tool tank. This usually happens while refilling the tool.

This is interesting!
If the fuel filter is working properly, but the lawn mower does not start, then you should make sure that the fuel hose is placed in the fuel. After all, there are cases when the hose together with the filter is simply disconnected from the main tube, which makes it impossible to start the engine of the tool.

Reliability of built-in filters

It is these devices that often become an obstacle that prevents the classic trimmer from starting. The filter provided by the manufacturers is responsible for high-quality cleaning of the air entering the carburetor. A clogged cleaning unit can lead to the fact that oxygen enters the internal compartment of the unit in smaller quantities or its supply stops altogether. You can determine if the air filter is faulty in a fairly simple and accessible way:

Dismantle the device and carefully inspect it.
If no blockages are detected with the naked eye, then try starting the lawn mower without a filter. This part needs to be replaced only if the trimmer starts up successfully.
You can use a stream of compressed air to clean the air filter. But if the cleaning device has been in use for a long time, then it is more advisable to replace it.

It is worth noting that trimmers do not start due to a clogged air filter in the rarest cases. Most often, this device affects the stability of the engine. A more real reason lies in a clogged fuel filter. This unit is located in the unit tank. If the trimmer has been used for more than two years, then it is imperative to check the filter, which may impede the flow of fuel to the carburetor.

If the user is sure that the main problem lies in the fuel cleaning element, then the following steps must be performed:

Carefully remove the filter.
Try to start the lawn mower.

If the device starts up quickly enough, then the problem lies in the fuel filter.

The service life of this unit can be significantly reduced by long-term storage of fuel in the tool’s engaged tank, as well as by accidental entry of small debris and dust into the trimmer’s tank. But if the filter is working properly and the lawn mower still won’t start, then you need to check the fuel hose. Situations often occur when the hose together with the filter are disconnected from the main pipe, which inevitably leads to the inability to start the engine.

How does the breather affect the ability to start a lawn mower engine?

Having ruled out malfunctions of the lawnmower filters, it is necessary to check the breather. A breather is a part that is responsible for normalizing the pressure in the tank. When the fuel gradually leaves the tank into the carburetor, the pressure increases (a vacuum is created). To relieve the vacuum inside the tank, a breather is used - a kind of valve that is located on the lid of the tool's tank. This valve has a filter element through which the air entering the tank is filtered.

Over time, the filter becomes clogged and causes a vacuum to be created in the gas tank. It’s trite, but in 30% of cases, a trimmer malfunction in the form of the inability to start it is associated with a clogged breather. The breather on the trimmer can be cleaned and the tool can be used again. You can make sure that the cause of the trimmer malfunction is the breather as follows:

Unscrew the gas tank cap
If air bleeds out when unscrewing, then we can assume with 100% certainty that the breather has failed
Screw on the cap and start the lawn mower engine. If the trimmer starts, but after a while (when the amount of fuel in the tank decreases) it stalls, then it is necessary to clean the breather

You can clean the breather using a regular sewing needle. Many people don’t even know about this important detail, so they often don’t understand what to do when the engine of the mowing gas trimmer does not start. Answering the question of the effect of the breather on starting the engine, it must be said that it has a direct effect. Excessive pressure in the tank prevents fuel from flowing to the carburetor, so the engine does not start.

Diagnostics of the candle channel

What to do if the fuel mixture used is in perfect order, but the gasoline trimmer still does not start? The reasons for the failure of the mechanism lie in excessive moisture in the spark plug channel. To diagnose and resolve the problem, you must do the following:

Unscrew the spark plug. Wipe it thoroughly and then dry it.
Drain excess fuel in the chamber through the appropriate spark plug hole.
Clean the old spark plug if there is carbon deposits on its surface. You can cope with the task using an ordinary ladies' nail file, also called a needle file.
To install the element in place, set a gap of 1 mm. To check the parameter, just place a coin in the gap.
Reassemble the functional block.
Try starting the trimmer.

READ How to Change Line on a Husqvarna 128r Trimmer

It is recommended to dry the spark plug channel for at least half an hour. But you should not resort to calcining its parts. After all, heating the spark plug leads to its ultimate damage. What to do if the service of the functional block is carried out in accordance with the above tips, but the trimmer does not start, a spark occurs here? Then it is worth treating the threaded connection with gasoline. The latter does not need to be heavily soaked in fuel. It just needs to be slightly moistened. Such actions should be taken to ensure ignition. After all, it seems like the candle ; in a completely dry chamber there simply won’t be anything to ignite.

the trimmer does not start , it is worth assessing the quality of the contact between the high-voltage wire and the spark plug. If there is no spark (if there is a reliable connection between the indicated elements), most likely the problem is caused by a breakdown of the ignition unit. In this situation, you will have to turn to the services of specialists who will reinstall the unit.

The muffler is clogged and the gas trimmer cannot be started

What else could be the reason why the gas trimmer engine cannot be started? Even before resorting to more drastic actions, you should check the serviceability of the muffler or exhaust duct. This does not apply to new trimmers, which have practically no special output. If the trimmer is already many years old, and the tool has not been subjected to diagnostic measures, then the muffler should be checked for clogging.

If the muffler on your lawn mower is clogged, there is nowhere for the exhaust gases to escape, making it impossible to start the engine. The exhaust channel cannot become clogged overnight, so the following signs should have appeared the day before:

An increase in the sound of the engine, which is associated with overcoming great resistance by the exhaust gases to release them
Black smoke from the muffler is carbon deposits that settle on the walls of the exhaust system
Unstable engine operation
The engine stalls on its own when idling

This factor can be excluded or confirmed by inspecting the exhaust system. If the anti-spark mesh is significantly clogged, then undoubtedly the reason for the inability to start the engine lies in the exhaust channel. The mesh must be cleaned, but this must be done carefully, since black soot is a very dangerous carcinogen that can cause serious diseases of the human respiratory system. To clean the anti-spark mesh and the walls of the trimmer muffler, special products should be used, and work should be carried out using protective equipment.

Why won't my lawn mower start when it's hot?

It often happens that the lawn mower does not start when it is hot. In this regard, the question “why?” is absolutely logical. Basically, the cause of such a malfunction may be associated with the following technical components of the instrument:

Fuel tank.
Exhaust channel.
Breather.
Starter for trimmer.

One of the most common breakdowns that cause the gas trimmer to not start when hot is a clog in the air filter area. Improper preparation of the fuel mixture, as well as its quality, also become the cause of failures during the operation of the unit. Often the reason that a 4-stroke brush cutter does not want to start is excessive moisture in the spark plug channel.

The stable functioning of the tool can also be disrupted due to the accumulation of dirt in the exhaust channel, in other words, the accumulation of a mass of debris on the muffler mesh.

The trimmer does not start when cold, what are the reasons?

First, let's look at the situation when it is impossible to start the engine of a lawn mower when it is cold. What does this mean? Surely mowers have encountered a situation where the trimmer starts up just fine when hot, but as soon as you take a short break, a problem arises. This is a problem with starting the engine after it has cooled down. What could be the reason? Of course, no one excluded all the factors described above, but if the situation occurs constantly, then there is no need to check them. If the lawn mower starts well when it’s hot, but problems arise when it’s cold, then you should look for the reasons inside the CPG (cylinder-piston group).

To identify the problem, you will need to use a compression gauge. We screw the compression gauge into the hole instead of a spark plug, and then activate the starter handle. We measure the pressure inside the cylinder - compression. The compression value should be on the order of 8-12 atmospheres. After the tool has warmed up (it is enough to work for 15-20 minutes), you should repeat the checking procedure. If the compression on a hot engine is below 8 atmospheres, then a CPG malfunction is likely. This means that the rings, piston and cylinder walls are worn.

The situation can be corrected by replacing the CPG. When replacing, it is important to take into account such a recommendation as generously lubricating the parts with engine oil inside the cylinder. This is necessary to ensure that scuffing does not occur in the first minutes of starting a new cylinder with a piston.

When engine compression decreases, fuel consumption increases and tool performance also decreases. It is possible to work with such a tool, but wear increases with each subsequent hour of work. One day it will be impossible to start the lawn mower at all, even when warming up.

This is interesting! You can warm up the engine of a lawn mower with low compression by pulling the starter handle. When warmed up, the metal expands, thereby increasing compression.

Diagnostic features

From a technical point of view, trimmers are complex devices. Of the characteristics of this, it is strongly recommended that you carefully study the corresponding annotation before using them. But in fact, some people ignore it, and often later find themselves in situations where the gasoline trimmer does not start or develops poorly during operation. It is worth noting that you can encounter similar problems when purchasing new models of equipment.

The key to effective and prompt repair will, of course, be qualified diagnostics of the device. To identify flaws, you will have to inspect and test, first, the main elements. The list of these includes spark plugs, a tank, filter units and valves of the fuel complex of accounting programs. Based on practice, often malfunctions of these parts themselves become a prerequisite for the fact that the lawn mower does not start. The quality and correctness of the production of the fuel mixture deserves special attention, especially if we discuss about two-stroke engines. Regarding this parameter, you should correctly follow the manufacturer’s advice in order to avoid serious breakdowns and costly repairs. If the passage, for example, with a piston group of an internal combustion engine, the costs can reach up to 70 percent of the price of new equipment.

READ How much oil to put in the trimmer

Often, owners of trimmers have to deal with situations where the indicated mixture is of high quality, the carburetor is working properly and adjusted, but the device still shows no signs of life when trying to start the engine. In similar cases, you should check the condition of the candle. The following steps will allow you to remove the problem:

turn out the spark plug;
wipe and dry the part (calcination is unnecessary);
remove fuel and dry the spark plug channel for a period of 30–40 minutes; such actions will allow you to avoid flooding the spark plug during the next startup attempt;
completely remove traces of soot using a needle file, or sandpaper;
set the appropriate gap;
put the candle in place.

If the spark plug turns out to be working and the seat is 100 percent dry, but the scythe engine does not start, then you should moisten the threads with gasoline. It is worth keeping in mind that, regardless of the characteristics of the spark produced, at first in a completely dry chamber there will simply be nothing to ignite. Faced with that goal, If there is no spark, you should pay attention to checking the contact between the high-voltage wiring and the spark plugs. If this connection turns out to be of good quality, then you need to check the functionality of the control unit that allows you to maintain accounting (software) of the ignition. In such cases, you cannot do without the services of a qualified specialist.

The next step in diagnosing a gasoline scythe is to check the condition of the filters. Often, the mower poorly or does not start at all when cold because the air filter is clogged. There is an option to identify this malfunction by eliminating it from the accounting system. If after this the scythe starts up, you will have to clean or replace this element. Experienced users always recommend periodically blowing out the air filter to further extend its service life.

The described tool may also fail to start due to problems with the gasoline supply caused by a dirty fuel filter. To quickly and effectively fix an identical breakdown, you just need to replace the filter element with a new one. It is important to remember that the suction pipe must be equipped with a filter, which is provided for in all instructions. Failure to comply with these rules and advice may result in expensive piston repairs. During diagnostics and searching for the source of problems with starting the mower, attention should be paid to the breather, which is responsible for stabilizing the pressure equalization in the fuel tank. Additionally, it is necessary to check the cleanliness of the exhaust channel and muffler mesh. You almost always encounter similar problems when troubleshooting old models.

The lawn mower engine does not want to start after winter

Often, with the onset of spring, most owners of lawn mowers complain about the inability to start the engine of this lawn-mowing tool. With what it can be connected? In order for the trimmer to start up well in the spring after winter storage, you need to learn how to properly care for it. How to properly store a lawn mower in winter is described in detail at the very end of the material. Now let’s figure out why it’s impossible to start the tool’s motor after winter.

One of the main reasons why a lawn mower won’t start after winter is fuel stagnation in the gas tank. If you do not drain the fuel from the tank and leave the tool for a long time, it will naturally be impossible to start the lawn mower. The properties of the mixture of gasoline and oil decrease, so as a fact we get a malfunction of the tool. Even if there is fuel mixture left in the trimmer from last year, it is recommended to drain it and refill with freshly prepared one. After this, launch the tool.

Another reason could be a faulty air damper. When closing it manually, the valve itself may not work, so you start the lawn mower with the air damper fully open. In this case, the tool will not start when cold, as there is a large air leak. The video below explains why the trimmer does not start when cold.

In addition to these reasons for the impossibility of starting the engine of a lawn mower, there are others that are also important to mention:

Dampness of the spark plug electrodes - before starting the trimmer after winter, you should unscrew the spark plug, inspect it, clean it, dry it and set the gap
Damage to the high voltage wire. During storage of the instrument, the high-voltage wire could crack, become damaged, or be chewed by mice. Make sure the armored wire is intact if the trimmer does not start after winter
Oxidation of wire contacts. This usually happens if the instrument is stored in a room with high humidity.
Check the serviceability of the ignition coil. Over the winter, this part could fail and cause difficulty starting the tool.
Carburetor adjustment - it is recommended to adjust the carburetor after winter. To do this, the tool must start, so if it is impossible to start, it is recommended to pour 20 grams of fuel mixture into the spark plug hole and start the engine
Carry out all the above actions, since during long-term storage the breather hole, filters could become clogged, and corrosion could form on the walls of the exhaust system

Carry out diagnostics of the tool, and only after that resort to more serious repairs - cleaning the carburetor.

The petrol trimmer will not start. floods the candle / the candle is always wet

Among the many events due to which the trimmer does not start, directly filling the spark plugs with the fuel mixture is considered more common. According to statistics, the second owner of the instrument faces an identical problem. Almost always, the candle is always wet for the following reasons:

READ Petrol Trimmer Bort Bbt 2300 Pro Review

When a gasoline trimmer does not start because the spark plug is constantly flooding, the user needs to remove excess fuel mixture, thoroughly clean the components that play a role in this process, and then blow out the spark plug, giving everything time to dry.

Regardless of how correctly you can choose a studio, whether you own an economical gas-powered tool made in China, or, in other words, use expensive models from a brand such as Husqvarna, cleaning the spark plug for a brush cutter is carried out in the following order:

Turn the tool over and run the starter until the excess fuel mixture is completely released.
Dismantle, blow out and clean the candle, leaving it to dry for 40 minutes.
A 100 percent dry spare part is put back.
An attempt to launch the tool, while still running hot.

By completing the above steps, you can easily remove malfunctions caused by the spark plug without any problems.

The trimmer does not start due to a carburetor malfunction

One of the most difficult reasons for the inability to start a lawn mower is the carburetor. This mechanism is responsible for preparing and properly supplying the fuel-air mixture to the cylinder. If the carburetor is clogged or incorrectly adjusted, the lawn mower may not start or may not work properly. Detailed instructions on how to adjust the carburetor on a lawn mower are described in this material.

If the adjustment does not help restore stable operation of the tool’s engine, or the trimmer does not start at all, then you should remove the carburetor and repair it. All carburetor repairs involve disassembling it, cleaning all channels and components. If necessary, replace failed parts - membranes, filters, etc.

If suspicions fall on the carburetor, then you should pay attention to the following types of malfunctions:

The channels and jets are clogged - special liquids can be used for cleaning, but it is best to disassemble the mechanism and thoroughly wash it. The cause of clogging of the carburetor channels and jets is storing the tool with fuel in the tank.
Wear of carburetor gaskets - rubber seals contribute to the leakage of the mechanism, resulting in poor functioning
Malfunction of carburetor membranes - they are responsible for pumping fuel into the device

To ensure that the CPG is faulty, you should perform a compression test as described above.

Chainsaw wet spark plug: why and what to do

You can use a special flush to clean the carburetor.

If the carburetor gaskets are worn out, they need to be replaced. And if the tightness of this device is broken, you will have to identify the faulty carburetor part and replace it.
The trimmer may not start due to wear on the piston group. However, it is better to change such parts of the lawn mower at a service center.

Trimmer line - which one to choose? Immediately after purchasing a grass trimmer, we are faced with a lot of questions - how to use it correctly, how to refuel it (if we are talking about a gasoline tool) and, of course, which fishing line is best to choose. Find the answer to the last question in the article.	How to quickly remove a stump without uprooting it? Many gardeners sooner or later are faced with the need to cut down trees growing on their property. After this, stumps remain, and if the trees were of significant size, uprooting them is very problematic. The article talks about alternative ways to get rid of stumps.
Treatment of currants in the fall from pests and diseases Almost every summer resident grows currants, which are loved because of their taste and beneficial properties. It requires proper care, which includes treating plants from pests and diseases. The features of these autumn events are described in the article.	How to choose a gasoline grass trimmer? A beautiful well-groomed lawn is a decoration for any area. And regular haircuts help maintain its attractiveness. You can't do this without a lawn mower or trimmer. In this article we will talk about the intricacies of choosing a gasoline trimmer.

How to properly store a lawn mower and eliminate problems with starting it

Its launch depends on the correct approach to storing the trimmer. Moreover, this applies not only to long-term winter storage. How to properly store a gasoline trimmer, in order to protect yourself from problems with difficulty starting it, you need to take into account a number of the following recommendations:

Before putting the tool away for winter storage, you should drain the fuel from the tank. In addition, remaining fuel also needs to be removed, and this can be done by starting the engine, letting it run for a while until it stalls
It is advisable to store the instrument in a dry place
Before starting the engine after a long pause of more than 2-3 months, it is necessary to first inspect the spark plug electrodes, as well as check the main components - the air filter, high-voltage wire, etc.
When using the tool, you need to take into account that overheating of the motor negatively affects the service life, so you need to take breaks while working, especially if a trimmer with a two-stroke engine is used for work. Units with four-stroke engines are not only more powerful, but also more durable
After winter, the first thing you need to do is pour a little oil into the spark plug hole, first moving the piston to its dead center. This is necessary in order to lubricate the CPG parts when starting the engine, thereby preventing their rapid wear.

Only with the right approach to finding the reasons why the trimmer does not start can you find and fix the problem yourself. Moreover, for this you do not need to be a specialist or thoroughly understand the design of gasoline units. Proceed in order in the sequence presented in the material, and restoring the functionality of the lawn mower will be as easy as shelling pears.

Preventive measures

To ensure that the purchased trimmer is always in good condition, it is necessary to use and store this unit as correctly as possible. Manufacturers recommend carefully following a few basic rules:

Fill the lawn mower tank with only high-quality fuel.
Carry out technical inspection and adjustment of the main mechanical elements of the device regularly and in a timely manner.
Try to avoid overloading the trimmer during operation.
After each use, check the trimmer for the absence of carbon deposits and specific oxides on the surface of the ignition system mechanisms.

To ensure that the trimmer is always in working order, you need to prepare it as much as possible for storage during the cold season. The first step is to disassemble the unit step by step, and then perform a thorough cleaning and careful rinsing of the components. Carefully inspect the multifunction units for any damage. If necessary, eliminate deformations of parts.

To store the lawn mower, you need to fill the gearbox with a sufficient amount of oil. The air filter must be cleaned; you can also disassemble and wash the engine of the device. All mechanisms are thoroughly dried, and the moving mechanisms are lubricated with a high-quality product. To treat the piston system, you must first remove the spark plug. The piston is carefully moved to the extreme position in order to be able to pour a small amount of oil into the spark plug hole and smoothly rotate the crankshaft.

If the trimmer will be stored outside the house until the next season, then the engine must be wrapped in oily rags. This approach will avoid the development of corrosion on the surface of critical components of the unit.

Recommendations for use

The stability of the operation of any brush cutter and the absence of problems with starting up units of similar devices directly depend on the aspects in which the tool is used and the maintenance characteristics. We are talking about the following basic rules:

when working, it is necessary to pay special attention to the cooling system and other parts; It is strongly recommended to promptly and thoroughly clean the channels located on the body of the scythe and the starter ribs;
During the processing of various parts, solvents, gasoline, kerosene and other active agents are used;
the indicated work should be carried out after the unit has completely cooled down;
Our client must follow the rules outlined in the relevant instructions drawn up by the developers of the tool being described, which will allow us to avoid overloads in a warm engine, which is usually the most common cause of serious breakdowns;
our client is left with the remaining fuel in the internal combustion engine, which should be completely drained before long breaks in the operation of the scythe; It is worth considering that the gasoline-oil mixture quite quickly breaks down into so-called heavy fractions, which inevitably clog the carburetor;
after removing the fuel, you need to start the engine and let it run at idle until the torque is correctly set until it stalls; in a similar way, the remaining mixture will be completely eliminated from the internal combustion engine.

Particular attention must be paid to preparing the instrument for long-term seasonal storage. This should be done with the goal of minimizing the risk of problems with starting the engine. Proper preparation contains the following manipulations:

completely disassemble the trimmer;
Thoroughly rinse and clean our client remains with the elements where there is access;
inspect the parts of the lawn mower in order to identify deficiencies (mechanical damage discovered during this process should be removed);
pour engine oil into the gearbox;
perform high-quality cleaning of the air filter element from clogging;
Having the appropriate knowledge and practical capabilities, the power plant is partially disassembled, followed by purging and lubrication of the moving parts;
wrap the assembled gasoline scythe with a pre-oiled rag.

In addition to everything already listed, it is necessary to lubricate the piston group. This popular rumor method provides for the following easy manipulations:

remove the candle;
use the starter to move the piston to top dead center (TDC);
pour a small amount of engine oil into the cylinder;
Turn the crankshaft several times.

Regardless of the price and brand of equipment, our client should do the right thing by only requiring the appropriate instructions and following the advice of developers and experienced experts. Now detailed information regarding the correct use of identical equipment can be easily found on numerous specialized websites and forums.

Next, watch the video on how to find and remove the reason why the gasoline trimmer does not start.

Where to start diagnosing a lawn mower

If the lawn mower does not start or stalls immediately after starting, it is necessary to sequentially check all the main components and assemblies. 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 the main problems, which can be eliminated after a thorough inspection.

Checking the fuel mixture

Before starting the gasoline scythe engine, check the availability and quality of the fuel mixture. Don’t save money, don’t be greedy, and don’t be “clever” in this matter. Repairing or replacing the piston group will cost you too much (sometimes up to 70% of the cost of a new tool). The oil-fuel mixture must be prepared strictly according to the instructions. Calculate its quantity based on real needs. The excess gasoline remaining after work loses its quality over time.

We diagnose the spark plug and spark plug channel

If the quality of the fuel mixture is not in doubt, and the lawn mower stalls when starting, then the cause may be a flooded spark plug. Here, a regular spark plug wrench (surely every motorist has one) and a spare spark plug are suitable for repairs.

We unscrew the candle and wipe it;
Dry it thoroughly (do not heat it);
We drain the excess fuel in the chamber through the spark plug hole and dry it;
We clean the old candle from carbon deposits using a file or a lady’s nail file;
We set the gap with a distance of 1 mm (you can check it with any coin);
We return everything to its place and try to start the trimmer.

You need to dry the canal for at least 30–40 minutes. Otherwise, there is a risk of re-filling a new spark plug.

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

If the trimmer engine still does not start, a reason such as lack of spark due to poor contact between the spark plugs and the high-voltage wire should be excluded. If the connection is good, but there is still no spark, most likely your ignition unit has failed. Here you won’t be able to do without a specialist, since the part is not repaired, but sold as a single unit.

Diagnostics of lawn mower filters

Another reason why a gas scythe stalls may be the air filter. To eliminate this, try removing the filter and starting the trimmer without it. If it works out, 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 gasoline trimmer may not start due to contamination of the fuel filter. This is the next stage 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 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, “delicate” branded models of 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. When this unit becomes clogged, a vacuum is created in the tank, preventing the supply of fuel. The problem can be resolved by cleaning the breather. You can use a regular needle for cleaning.

The normal operation of scythes with internal combustion engines may be disrupted due to dirt getting into the exhaust channel or clogging of the muffler mesh. This problem occurs on older generation models. The issue can be resolved by traditional cleaning and removal of the anti-spark mesh.

Flooded lawnmower engine.

If on a wet spark plug it is still possible for at least some spark discharge to appear on the electrodes, then on a “flooded” plug a spark discharge will no longer be possible. We hear about “flooded” spark plugs more often than about “flooded” engines. It’s even hard for many to imagine such an engine until they experience it personally.

A wet spark plug or a flooded spark plug is the main sign of either a non-functioning spark plug, a lack of high-voltage voltage at the spark plug electrodes, or an over-enrichment of the fuel mixture supplied to the engine working chamber.

Additionally, this includes cases with low-quality fuel, low high-voltage voltage and low compression ratio. As a rule, one thing entails some other manifestations and one can easily get confused in determining the main, underlying cause of the malfunction.

Spark plug.

Another lawn mower or gas trimmer fell into our hands and they could not start the engine. Even no recommendations from observers and “friendly” neighbors helped. The spark plugs were also replaced with new ones, but there was no result, and each successive spark plug came out wet.

Lawnmower engine air filter.

The gas trimmer engine was opened in stages. The air filter ring was completely wetted with fuel. There was a large amount of fuel in the compartment where the filter element is installed.

The throughput of the wet filter decreased, and even with a dry spark plug, the engine could not start due to the wet filter element blocking the supply of the required amount of air. The spark plug electrodes immediately flooded with fuel during the first attempt to start the engine.

Muffler for lawn mower.

An oil stain was clearly visible through the muffler mounting holes on one of the mounting studs. Traces of oil can appear when the fastening nuts are loosely tightened, when waste oil vapors along with exhaust gases leak through weak seals, but on this lawn mower the nuts were tightened to the required force.

And in the muffler itself we found about 50...60 ml of fuel. Not oil, but the same fuel that was in the fuel tank.

Petrol mower engine.

When opening the engine, we expected to find some surprise, and this was not in vain. There was a certain amount of dense soot deposits on the piston. Loaded piston rings and a layer of carbon on the piston indicated that when working with a lawn mower, the temperature of the engine, which was running on an over-enriched mixture, was exceeded.

Many manufacturers write directly on the container that the oil has good anti-wear, lubricating, anti-corrosion and temperature properties. But none of them will write: “Don’t overheat the engine!” or “Follow our recommendations strictly!” It’s hard to say what they poured in instead of oil, or whether they poured in too much oil.

Crankcase.

What surprised us most was the engine crankcase, which turned out to be filled to the brim with fuel. It happens when a certain amount of fuel collects in the engine crankcase, but it is rare for us that the crankcase is completely filled with fuel.

The engine worked 'by the sweat of its brow', and the operator did not pay attention to fuel consumption, increased smoke, and decreased engine speed. The lawnmower engine was flooded to the very edges of the crankcase.

Lawn mower carburetor.

There were no difficulties when disassembling the carburetor. The outside of the lawn mower's carburetor was wet and dirty, which indicated a fuel leak, but we did not find the leakage itself during an external inspection.

And inside the carburetor there were dense deposits located along the edge of the seat hole of one of the membrane valves, which indicated poor performance of this valve when its petal was not pressed tightly against the seat.

Proper care of a chainsaw

There are no unnecessary phrases in the operating instructions; everything that is offered is aimed at the smooth operation of the gasoline pump. Cleaning all parts after each work cycle makes it easier to remove unhardened residues and dirt. Clean only cooled parts. This method contributes to the quality of air cooling of the engine and gearbox.

For refueling, you must use fuel with the recommended oil in the instructions. If the fuel mixture remains in the fuel tank, the oil will float and, upon startup, land on the damper, impairing its adjustment. The mixture may settle and clog the fuel in the carburetor.

When storing equipment for the winter, inspect and lubricate the gearbox and piston system, wrap the entire saw in an oiled rag and store it in a dry place.

It is impossible, and 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 gear and motor increases. The frayed piece of wire flies at the speed of a bullet while being disconnected. Effective mowing can cause rapid wear on the engine piston. For greater mowing efficiency, it is suggested to use a star line profile.

When caring for their garden, sometimes people have to deal with the fact that their lawn mower will not start. There are several reasons for the failure of this tool.

The brush cutter does not start - reasons

Improper storage, a long break in operation, untimely maintenance and other factors lead to the fact that the lawn mower may stop starting.

Diagnosis of the causes should begin with checking the main components - the fuel tank, spark plugs and spark plug channel, air and fuel filters, breather, exhaust channel. Most often, problems are associated with one of these components, and a thorough inspection of them will help determine why the lawn mower does not start.

If you use low-quality fuel (below AI-92), this can lead to breakdown of the cylinder-piston system, the repair of which will cost about a third of the cost

In addition, it is important to follow the correct ratio of gasoline and oil specified in the owner's manual for your specific model

Engine operation can also be hampered by a dirty fuel filter. If this problem is detected, the filter must be replaced. It wouldn't hurt to check the air filter as well. If it becomes dirty, it is necessary to dismantle it, wash it in water and detergents, dry it, lubricate it with oil and put it back in place. Spark plugs that show no signs of life must be replaced with new ones.

Sometimes the brush cutter starts normally, but then stalls. This is mainly due to incorrect carburetor settings or misalignment. You can determine that this is the reason by the vibrations that are noticeable during operation. You need to adjust the fuel supply by following the instructions for the tool.

The brush cutter does not start well when hot

When the brush cutter was working properly, and after a short break does not want to start again, you need to press the gas trigger and sharply pull the starter cord several times in a row until the engine starts and only then release the gas trigger.

The brush cutter does not start when cold

When starting a cold brush cutter, pressing on the gas, on the contrary, is not recommended. You need to tilt the lawn mower so that the air filter is at the top and press the choke button 5-6 times, then set the function switch lever to the “Start” position and pull the cord several times until the engine starts. After a few seconds of operation of the scythe, the launch system can be turned off.

What to do if the lawn mower does not start? In this article we will look at the main causes of this breakdown.

Most often, the lawn mower refuses to start because fuel floods the spark plug. This can happen because worn injectors supply too much fuel to the combustion chamber, and the excess floods the spark plug, preventing it from generating a spark. If the spark plug is always wet, this may indicate wear on the gaskets, which is why leaking oil prevents spark formation. If the spark plug is dry, but the brush cutter still does not start, then first you need to replace the spark plug itself.

Another common reason is that the 4-stroke lawn mower refuses. Here we can recommend a simple test: press the trigger and pull the trigger cord several times. If after this the engine still does not start, it means that your tool needs more detailed diagnostics followed by specialized repairs.

One reason for a flooded lawnmower engine.

After inspecting the main elements of the engine and interviewing the owner of the lawn mower, we finally identified the reason that led to such consequences.

Inattention of the operator, who may have accidentally touched the choke control lever and switched it to the “OFF” operating state, in which the air supply was limited, implying the opening of the damper.

It is possible that the operator did not sufficiently understand the meaning of the ON and OFF damper position indicators and became confused.

In a word, the human factor is present in all unpleasant situations that occur during the operation of equipment.

Rules for operating and storing lawn mowers

In order for the lawn mower to start well in the future, you need to provide it with good storage and operating conditions:

During operation, carefully monitor the cooling system, carefully and promptly clean the channels in the housing, as well as the starter fins;
if necessary, use solvents, kerosene and other detergents for cleaning;
Do not clean the tool “hot” - let it cool down;
strictly follow the operating instructions, otherwise you may overheat the engine;
if you do not plan to use the lawn mower in the next month, you need to drain the fuel mixture from it, because over time it breaks down into heavy fractions that will definitely clog the carburetor channels;
After draining the fuel, let the trimmer idle until it stalls, this will help completely remove the remaining working mixture.

Before winter storage, take the following steps:

completely disassemble the braid, rinse and clean all the parts you can;
inspect the parts for damage, if necessary, eliminate distortions, tears, bends and any other defects;
pour a sufficient amount of oil into the gearbox and clean the air filter;
you can partially disassemble the motor, wash, blow and lubricate all moving parts;
in order to lubricate the piston, you need to unscrew the spark plug, use the starter to raise the piston to the dead center, pour a little oil into the spark plug hole and turn the crankshaft a couple of times;
If you store the lawn mower outside the house, wrap the engine with oily rags.

Remember, careful adherence to the rules will allow you to forget that it is difficult to start a lawn mower for several seasons.