lawnmower does not pump gasoline. Why does the lawnmower stop after starting??

Why the grass trimmer does not start: the causes of malfunction and how to fix them

It’s time to mow your lawn but your lawnmower isn’t working? It’s scary to imagine how you can keep your lawn in perfect condition with a hand tool, especially when you haven’t had to do it before. If the grass trimmer does not start, the causes may be very different, but most of them you can fix yourself.

You don’t need any special tools or specialized knowledge to do this. A little courage and free time to read this material. and the grass trimmer will not need to take to the master.

In this article we will tell you how to determine what is preventing the start, give you instructions on how to repair every single node and recommendations on how to avoid problems in the future. For clarity, you’ll find photos and videos that clearly parsed the most common breakdowns.

First, the spark plug

The first thing to do is unscrew the spark plug. If it is wet, then the ignition system is faulty. Try wiping the spark plug, stick it in its cap, put it to the engine, pull the starter. Is there a spark?? If not, you need to change the spark plug.

The spark plug replacement didn’t help? Then you need to look at the magneto, the cable, the ignition coil. The cable is tested, the coil is checked for resistance (multimeter in resistance measurement mode at 200 ohms, one contact to the ground, the other. to the output of the coil, should show 0.4 to 2 ohms).

Sometimes the magnets on the flywheel get dirty, or the key slips, and the ignition timing flies away. The Chinese shit throws up some surprises, but for the most part all can be detected visually.

It is definitely necessary to pay attention to the fouling of the spark plugs. If it is black, the plug is sooty, it means the mixture is rich, or you have mixed the fuel wrong. If the deposit is white, it means the fuel mixture is poor and the engine could die of fever. Ideally, the color should be brick-colored, light, without much buildup.

Again, if the plug is black and dead, do not immediately blame the carburetor and ignition. Screw in a new one, see what kind of deposit. Maybe it’s just a bad spark plug.

Key causes of breakdowns

lawnmowers and grass trimmers often stop starting after long periods of storage. To determine the cause of malfunction, you need to make multi-step diagnosis with special tools. In most cases, grass trimmers break down because of problems with the gas tank and filters.

Much depends on tool life. The older the machine, the more complicated the breakdown. Each grass trimmer part has its own recommended service life. When it comes to the end of its life, it is recommended to replace the lawnmower parts with new ones.

Problems with the fuel tank

Check the quality and specifications of the fuel and oil used before starting the mower.

To determine the correct amount of oil and fuel mixture, consult your owner’s manual. The fuel in the tank is filled only once, so that it can be used up during operation.

Fill the lawn trimmer with fuel as gently as possible. To minimize the chance of it falling outside the grass trimmer, you can use a standard funnel

If the fuel is left in the tank for a long time, after some time it will lose its key characteristics. Such gasoline can seriously harm the engine and lead to engine damage. For this reason it is not advisable to store large quantities of fuel.

It is not uncommon for lawn mowers to stop starting because they contain old fuel. In this case it is necessary to pour out the old mixture, clean the tank and pour new petrol into it.

The recommended fuel mixture specifications that should be used on your chain saw (i.e.ч. For the exact petrol/oil ratio, see the owner’s manual

At the same time, the fuel poured into the tank must have the appropriate physical and chemical characteristics. It is not recommended to use low-quality gasoline mixtures of unknown origin.

Most manufacturers of trimmers, for example, STIHL and Husqvarna, recommend filling the tank with gasoline of a brand not lower than AI-95. You can buy it at a trusted gas station.

The use of high-octane and high-quality fuel will determine how long the grass trimmer can last.

Troubleshooting spark plugs and the spark plug conduit

In the case of grass trimmer malfunctions, make sure that the spark plug passage is not flooded with combustible mixture. If the air damper is not moved to the open position in time, the spark plug will be flooded with gasoline when the engine is turned on.

To make sure that the lawn mower‘s starting problems are related to the spark plugs and the spark plug passage, the following steps should be taken:

  • unscrew the spark plug, clean and dry it, t.к. only dry plugs can be put into internal combustion cylinders;
  • Drain unused fuel from the hole where the spark plug was located;
  • remove the soot on the spark plug. you can do this with normal manicure tools (scissors or saw);
  • Reassemble the unit and restart the system.
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In most cases, these manipulations will make it possible to start the engine.

If the grass trimmer does not work after replacing the plugs, you need to check the spark. If it is not present, it is necessary to check the cable (use a tester), connecting the coil and the spark plug. If you find problems with the wire, you need to pull a new high-voltage cable.

Fuel line defects

If the grasshopper leaves a wet trail and there is no traction, this indicates problems with the fuel line. Its condition may be checked visually. there may be cracks and holes in the fuel line.

Usually leaks and any mechanical defects are quite visible and therefore easy to detect during a routine inspection.

Especially carefully you need to check the fuel line on the Chinese lawnmower, because it can be severely deformed (twisted or torn)

Irrespective of the character of the fault the defective conduit should be replaced with a new one. When picking up such components, you should choose original parts.

How not to get confused if the lawnmower does not start

The tool, despite its small size, is a complex technical device. If you study the instruction manual, it turns out that the reasons why the lawnmower does not start are known and can be eliminated. It is necessary to consistently exclude factors that make it difficult to start the tool. Usually you start with the more accessible units with an easy check to see if they are in good working order.


All the reasons why the lawnmower does not start, can be classified according to the specifics of the work of individual nodes. The service center classifies malfunctions:

  • engine failure (piston wear, bearing failure, cracked crankcase);
  • Fuel mixture malfunction. clogged pores in the air filter or carburetor malfunction
  • the ignition system does not work;
  • Malfunction of mechanical nature. leaky hoses, broken wires under the braid, broken tubes.

The user first needs to check whether there is fuel in the tank. Start according to the instructions, with the saw on its side. set the choke in the “closed” position, pump the fuel, switch on the ignition and make 3-4 jerks of the starter. If the engine is running, open the air damper. Lawn trimmer does not start. repeat operations with the air damper slightly open.

The lawnmower can’t run for long. The gearbox and the engine will overheat. You can mow no more than 15=20 minutes, making a five-minute break. Working time is halved on a hot afternoon. Cut short time when mowing weeds, sedges.

If it fails to start, start looking for the cause of the failure:

  • check up fuel quality;
  • Make sure that the spark plug and the cleanliness of the candle channel;
  • Check the cleanliness of the air filter;
  • Make sure that the fuel filter is not clogged;
  • Check that the breather plug is clean;
  • clean out exhaust duct.

complex causes will be, found in the diagnosis of malfunctions, leading to an overhaul of the carburetor. Such causes include clogging of carburetor internal passages, wear of the gasket on it and violation of tightness of internal halves with loss of vacuum. Repairing the lawnmower with your own hands if it does not start will require patience.

Eliminating the Reasons Reasons Your Lawnmower Won’t Start

The fuel mix should be prepared in precise proportions of gasoline and oil. Do not use a different brand of fuel. To avoid dirt, gasoline should stand in a glass or metal container for 2 days. Do not use plastic containers for storing fuel. Oil accurately measure with a medical syringe without a needle. Use only freshly mixed fuel and do not leave fuel in the tank. If the engine gets fretful and the lawnmower cuts down when you press the gas, it’s probably the fuel that’s to blame.

mower does not start when hot. pull the throttle trigger and yank the cord sharply several times until the engine starts, then put the trigger down. Doesn’t start. specialized repairs required.

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

  • Remove the spark plug from the soot and dirt, dry it, set the gap of 1 mm;
  • connect to the high-voltage wire and check for a spark by yanking the starter several times;
  • if there is no spark, check the continuity of the high-voltage wire;
  • replace the spark plug;
  • dry the spark plug passage;
  • At the same time check the operation of the ignition coil, it is defective, if the working spark plug does not spark.

if the ignition coil is defective, the lawnmower will not start when hot, it stops, or works intermittently.

Clean or replace the air and fuel filter to ensure the necessary flow of ingredients into the carburetor. The air filter can be washed in soapy water or replaced. If a nylon blade is used, wash it, replace the porous felt filler. Replace fuel filter gently, without leaving the suction pipe open. If the engine starts with the air cleaner removed, do you know if the air filter needs replacing? Whether you need to change the grid on the fuel supply, if the lawnmower does not start, will prompt a dry spark plug.

Breather plug, air inlet in the gas tank. If it is clogged, it creates a vacuum in the tank and the mixture does not flow to the carburetor. The hole can be blown with air or cleaned with a needle. Clean the air duct and remove the muffler’s anti-sparking mesh.

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Adjusting and tuning the carburetor

Maximal and minimal engine revolutions, even idling are regulated by the carburettor. The stable operation of the lawnmower depends on the amount of fuel mixture and air fed, their ratio. Mower will not start if carburetor is out of adjustment. The order of setting the unit for low rpm (L), high rpm (H) and idle (T) is regulated by the same-name screws:

  • The chainsaw should run for at least 10 minutes, as the adjustment is made on the hot.
  • Turn the screw H slowly to maximum RPM and then turn it ¼ turn counterclockwise to reduce the RPM.
  • Regulate the idle speed with the screw T, making sure that the grasshopper doesn’t rotate.
  • The L screw is adjusted by first opening the throttle as much as possible, and then gently reducing the revolutions to a steady minimum.

After adjustment and correct carburettor with cleaned filters and checked ignition should enable the engine to work. If the carburetor malfunctions, once it is repaired, the feed system will need to be adjusted again before starting the lawnmower.

grass trimmer leaks petrol.

The gasoline used in the brushcutter is AI 92. You can find the exact gasoline brand name in the instruction manual. It is useless to try to “force” the engine by filling it with gasoline of 95. This leads to overheating, unbalanced operation of the grass trimmer and breakage.

It is not recommended to leave fuel in the trimmer’s fuel tank during an extended work break. It is better to finish the day’s work after all the mixture is completely used up. If you do not do that, then, as overnight the gasoline from the engine will fly away, and a narrow film of oil remains, the carburetor jets will be clogged. This will cause difficulties with the next start of the engine.

It is also necessary to follow the safety rules when storing fuel. Probably fill up gasoline in a plastic water bottle. It is worth doing?

Under no circumstances should you store gasoline in a plastic water bottle. When mixing the fuel consistence accumulates a static charge, you can “catch” a spark.

That’s why gas stations do not allow filling gasoline in plastic cans, only in iron cans. Before pouring gasoline into the iron canister, it is better to put it on the ground, so it removes static from the body.

But there are situations when the usual manipulation of the brushcutter does not help. The engine still will not start. In this case we check the power system and the ignition, following the rule “the engine does not work if there is nothing to flame or ignite”.

How to start the lawnmower more easily? You need to know a few tricks for this

If your lawn mower does not start as easily as you would like it to, then here are a few tips to help you:

  • Put the tool on its side so that the air filter is at the top. What it will do? The fuel mixture will go right to the bottom of the carburetor. You can also remove the air filter and pour a couple of drops of mixture into the carburetor and then reinstall all the parts. The machine will start on its first try!
  • It is possible that the problem is in the plug, and then, unfortunately, the previous method will not help. But there is another! Unscrew the spark plug, check it for function and dry the combustion chamber. If the part does not give signs of life, replace it with a new one.
  • Universal advice that will help start as a lawnmower, and a saw with a snowblower. But it works if the spark plug is good, the fuel mixture is fresh, air and fuel filters are clean. So, close the flap of the carburetor and perform one movement of the starter. Then we open the choke and yank the starter 2-3 times again. Repeat the procedure, after 3-5 cycles the engine will start.

Why the grass trimmer does not start: the main faults and troubleshooting

As already noted, such situations are typical for trimmers that have been idle for a long period of time. Therefore, once a problem is detected, you should immediately engage in troubleshooting.

Fuel as source of problems

The first step is to check the presence of fuel and its quality. The first thing to make sure that there is fuel in the tank. Those who have purchased the unit recently, often forget that the grass trimmer needs to be refueled. If there is no fuel, then the equipment simply will not work.

If there is fuel in the tank, but the grass trimmer does not start, then the owner needs to check whether it operates correctly. In this case it is recommended to study the instructions. If the startup is performed correctly, the malfunction may cause improper mixture quality.

  • Oil. It must be special. designed for two-stroke engines. Save on the product is not recommended, since the term of operation of the equipment depends on the mixture. Grass trimmers with a four-stroke motor require pure gasoline, it is not mixed with oil.
  • Not only quality gasoline should be used, but also the brand recommended by the manufacturer of a particular model. If there is no way to find out what fuel is needed, it is recommended to choose either AI-95 or AI-92, and the latter gasoline is the favorite, because the former contains additives that react with the two-stroke oil. It is not advised to use other brands.
  • Correct preparation of fuel mixture for the gasoline thrifting machine. It has been noticed that at first maximum attention is paid to this stage, but over time, mowers begin to mix the composition “by eye”, and this is a serious mistake. The correct gasoline to oil ratio is 25:1. 40 ml of the second, two-stroke gasoline is needed per liter of the first. Engine oil, intended for the car, is not a suitable option, since at high temperature the liquid loses (partially) its lubricating properties.
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Correct storage conditions for the fuel mixture are important. To save time, some owners prepare it in advance to use in the coming weeks. This variant is contraindicated, as prepared fuel mixture quickly becomes unusable. The reason. oil precipitation. With such a change both petroleum products lose their properties. Even re-stirring is not able to restore the original quality of the fuel. Therefore, it is recommended to prepare a certain volume: 2 liters, no more.

If everything is all right with gasoline and oil, then proceed to the diagnosis. to check the spark plugs.

Spark plug and its condition

At this stage of diagnostics it is necessary to stop in detail. The majority of experienced owners, who are already familiar with the question of why the grass trimmer does not start, first of all check the condition of the spark plug contacts. This element is diagnosed as follows:

  • First, the spark plug is unscrewed, then inspected. If the electrodes are in perfect condition, they should have a soot, the color of which resembles brick. Wet element, or white, black fouling on the contacts indicates the presence of any malfunction. The pink and red color of the electrodes is proof of a large amount of additives in the fuel. This mixture must be replaced.
  • If the spark plug is wet, it means that there is unburned fuel in the combustion chamber. It is left in place. Clean and dry the contacts of the plug (burning is prohibited). After this stage, the plug is connected to a candlestick.
  • Then turn on the ignition and twist the starter handle. When there is nothing wrong with the element, it should produce a constant spark. If it is weak or completely absent, then the verdict is the same. you need to replace the spark plug.

There is another reason why the grass trimmer does not start. It is a large gap that has appeared between the contacts of the plug. The normal distance is 0.7-1 mm. To correctly adjust the gap between the electrodes, special probes are used.

If you don’t have such a device, use a folk method. The razor blade is broken, put its parts together. This “feeler gauge” is then inserted between the contacts. The ideal. blades that enter tightly.

The problem in the fuel line and carburetor

If there is a spark, but the grass trimmer still does not give signs of life, then the problem may lie in the fuel supply to the combustion chamber. To be sure that this assembly is to blame, perform the following actions:

lawnmower, does, pump, gasoline, stop, starting
  • Pour into a syringe or pour into the cap from a plastic bottle about 20 ml of fuel.
  • Then fuel is gently poured into the combustion chamber through the spark plug hole.
  • Put the spark plug back in its place, put a candle holder on, start the engine.

In the event that the grass trimmer started, the problem may be in the fuel line and carburetor. When there is no effect from the made manipulations, the diagnostics continues. check the high-voltage wire. If there is the slightest suspicion this consumable element is replaced with a new one.

What to do if the grass trimmer engine still refuses to work? In this difficult case, you can follow these recommendations:

  • If in doubt about the spark plug and the high-voltage line it is better to replace them at once.
  • If when checking a new spark plug, the appearance of the spark could not be achieved, then you can almost certainly say that the ignition unit is defective. the coil is out of order.

Checking its working order is simple: unscrew the plug, then lean it against the body of the grass trimmer. If you get no spark when the starter does not fire or if it does not fire every time, you need a new coil. This element can also be replaced.

How to clean and store the tool?

During the operation of the lawnmower, monitor the condition of the engine cooling system. Channels in the starter housing and the cylinder fins must always be clean. If you ignore this and continue to use the brushcutter, the engine may overheat and finally break down.

Proper care for the gasoline mower during operation allows you to use it for several consecutive seasons without major repairs

Allow the engine to cool before cleaning. Use a brush with a soft pile and wipe the dirt off the outside surface. Clean plastic parts with solvents, including kerosene, or special detergents.

At the end of the summer season the lawnmower should be prepared for a long period of storage. To do this, the fuel mixture is drained from the tank. Then starts the engine in order to exhaust the remainder of the fuel in the carburetor. The whole tool is well cleaned of dirt and sent to “winter hibernation”.

As you can see, you can do the lawn mower repair yourself. You should call a service center in case of serious failures. Compare the repair costs with the price of a new lawnmower. It may be more sensible to buy a new tool.

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