Chainsaw Won’T Start On Hot Cause

After winter, I can not start the chainsaw, what can you tell me

If the chainsaw is not used in winter or summer, then with the onset of spring, when it becomes necessary to harvest firewood, a malfunction is often observed in the form of the inability to start the engine of the tool. The reasons may be different, but the first step is to check the presence of gasoline in the tank. If the chainsaw has not been used for a long time, but fuel remains in the tank, then the difficulties in starting a two-stroke engine are associated with the cause of stagnation of fuel.

If the fuel in the tank has not been drained before storage, then there is a high probability that a plug has formed in the carburetor. You will need to disassemble the carburetor and clean it. In order not to resort to these steps, you can do the following:

  1. Unscrew the spark plug and inspect it. If it is dry and has the correct brown color, then no fuel is being supplied to the cylinder.
  2. 20 grams of the fuel mixture is drawn into a syringe and sprayed into the cylinder
  3. The spark plug is twisted and the engine is started
  4. If the ignition system is working properly, the chainsaw will start

When the engine is started, the resulting plug in the carburetor will break through and the engine will run normally. If the engine starts and stalls on a chainsaw, then the procedure for adding fuel to the cylinder should be repeated several times. If the attempts end unsuccessfully, then you need to clean the carburetor, but first check the serviceability of the fuel and air filters, the ignition module and clean the exhaust channel (muffler).

Difficulties with starting a chainsaw cannot be ruled out due to such reasons:

  • Damping the electrodes of the candle
  • Oxidation of the contacts of the wires of the ignition module
  • Damage to the insulation of the high-voltage wire
  • Failure of the ignition coil
  • The need to adjust the carburetor

Difficulties with starting chainsaws arise sooner or later. It all depends not only on the quality of the tool and its price, but also on the features of the care, operation and storage of the tool. With proper care and storage of the tool, you will never have problems starting the engine of your chainsaw.

The main reasons why the chainsaw won’t start

When the chainsaw does not start, the search for the cause should begin with diagnostic procedures. To carry them out, it is not at all necessary to understand the device of the gasoline tool, and it is enough to follow the sequence of actions. Common reasons why your chainsaw won’t start are:

  1. Fuel line malfunction. From the tank, fuel in the form of gasoline with oil flows through the fuel line to the carburetor. The carburetor membrane, which acts as a pump, is responsible for its transportation. If there is no fuel in the tank, then of course the chainsaw will not start, so the first thing to do is make sure that there is fuel in the gas tank.
  2. Ignition system. Most often that the chainsaw engine does not start, the spark plug is to blame. This is due to the fact that it has a certain resource, and if the tool is used often and for a long time, then the candle fails. After making sure that there is fuel in the tank, you need to check the condition of the spark plug
  3. Filter elements are fuel and air cleaners that prevent fine grains of sand from entering the carburetor and cylinder. The fuel filter cleans the fuel, and it is located on the fuel supply line in the gas tank. The air cleaner is located on the carburetor, and limits the ingress of chips and sawdust into the carburetor
  4. The breather or pressure equalizer is the smallest element, which is often the main reason that the chainsaw will not start. The main symptom of a breather malfunction is when the engine stalls during operation
  5. Muffler or exhaust channel. During the operation of the tool, carbon deposits settle on the walls of the exhaust system. As a result, the exhaust gases have nowhere to go, and therefore the chainsaw will not start, and if it starts, it immediately stalls
  6. The carburetor is already a more serious malfunction, which can be eliminated by cleaning the device responsible for mixing fuel with air and supplying the finished mixture to the cylinder. Plugging of the channels and jets of the carburetor leads to the fact that the engine will not start
  7. The CPG is the most extreme reason why the chainsaw won’t start. The compression gauge will help to make sure of the wear of the cylinder-piston group. Having measured the compression of the chainsaw, you can draw the appropriate conclusion about the health of the engine itself
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These are all the components that need to be checked in order to find and eliminate the cause of the inability to start the engine of the chainsaw. In more detail each type of malfunction, as well as ways to eliminate them, we will consider further.

What is a breather and how does it affect the reasons for the inability to start a chainsaw

Few of the sawers know about the existence of such an element on a chainsaw as a breather. This is one of the important parts of the tool, which is responsible for balancing the pressure in the fuel tank. The principle of operation of the breather on a chainsaw is that when the amount of fuel in the tank decreases, a vacuum or vacuum occurs. The less fuel in the tank, the higher the pressure, which becomes an obstacle to the passage of fuel into the carburetor. To reduce the pressure in the tank, a breather is used, which is a valve that allows air to pass in one direction.

If the breather inlet is clogged, then air does not enter the tank, which means that pressure begins to increase. There is a breather on the fuel tank cap of the chainsaw (depending on the model), and if the two-stroke engine of the tool does not start, it is necessary to check the breather. It is quite simple to make sure that the breather is faulty:

  • Unscrew the fuel tank cap. If air bleeds, then this indirectly indicates a malfunction of the pressure regulator
  • Screw the gas cap back on, then try to start the engine again. If the engine starts, but after a while it stalls, then the breather needs to be cleaned
  • Another way to check if the breather is working is to disconnect the fuel hose from the carburetor. If fuel flows out of it intermittently, then the device is working properly. If the trickle is weak and intermittent, then you need to clean the breather on the chainsaw to start the engine

The breather (fuel tank cap valve) is cleaned with a needle. If the breather is heavily clogged, you will need to remove the filter element and clean it. On different models of chainsaws, the location of the breather is different (on most models it is located in the gas tank cap). Below is the process of cleaning the breather using the example of a Husqvarna chainsaw.

Is there fuel in the tank and what is its quality

Checking the presence of fuel in the tank is the first thing to start diagnostics with. Even if visually there is still fuel in the tank, make sure that the fuel line is lowered into it. If the fuel in the tank is at the bottom, then this is the main reason that it is impossible to start the engine. After adding fuel to the tank, it is necessary to pump the system, and only then carry out a test run of the engine.

If there is enough fuel in the tank, make sure that the supply hose inside the tank is not detached. On some models of chainsaws, such a malfunction is a “disease”. If the tank is full, this does not mean at all that the breakdown is not related to the fuel system. Check the quality of the fuel (oil and gasoline). Gasoline for chainsaws is used mainly of the AI-92 brand. As oil, you need to use only a special two-stroke, but not an engine oil or even working off.

The prepared fuel mixture cannot be stored for more than 2 weeks, as the mixture begins to lose its properties, which negatively affects not only the operation of the engine, but also its starting. How does a poor-quality mixture affect engine starting, you ask? Everything is very simple, with long-term storage of the mixture, oil precipitates, which leads to clogging of the channels and jets of the carburetor.

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The instructions for each brand of chainsaw indicate recommendations on the ratio in which gasoline and oil should be diluted. It is this recommendation that should be followed when preparing a mixture for a two-stroke engine of a chainsaw, otherwise it will significantly reduce the life of your tool.

If the chainsaw won’t start anyway, what to do

The above are the main reasons why the chainsaw does not start. over, this applies to tools of different brands Stihl, Husqvarna, Partner, Makita, Champion and others. Chainsaws Friendship have a different principle of operation, but in general, the search for a malfunction should begin with the ignition system, or rather, inspect the condition of the spark plug electrodes. If the manipulations carried out do not help to obtain the desired result, then it is necessary to resort to more serious actions. This means that you need to follow these steps:

  1. Check the serviceability of the carburetor and adjust it
  2. Measure the amount of compression of the engine, and then make an appropriate conclusion about its serviceability
  3. Compression in the crankcase is checked

Checking the compression in the cylinder allows you to assess the condition and serviceability of the CPG. To measure compression, you need a compression meter. It is screwed into the spark plug hole, after which the starter handle is pulled. The compressor shows the corresponding cylinder pressure. This value should be at the level of 8-12 atmospheres.

If the pressure is significantly lower, then this is a direct sign of a device malfunction. In case of malfunction, the cylinder-piston group is replaced with a new one. When installing a new CPG, it is necessary to carefully treat all parts with oil so that chips and scuffs do not form at the time of engine start.

If there is no compression in the crankcase, then the chainsaw will also not start. The reason for the decrease in the pressure in the crankcase is the gasket, or rather its damage. This gasket is placed between the cylinder and the crankcase and, to make sure it is working properly, the following manipulations should be performed:

  1. Disconnect the fuel line from the tank
  2. Lower the tube into a container with a prepared mixture of gasoline and oil
  3. Start the chainsaw engine
  4. If the engine starts and fuel is sucked in, then this indicates the serviceability of the gasket.

If the fuel is not sucked in, then the crankcase gasket needs to be replaced.

Chainsaw Won'T Start On Hot Cause

The carburetor is an important and most difficult part of a chainsaw. If all of the above steps did not help to get a positive result, then this indicates that the carburetor is faulty. The main malfunction of the carburetor is the clogging of its channels and jets. Membranes and other elements fail less often. In any case, you will need to disassemble the chainsaw carburetor, clean it and replace the failed parts.

As you can see, there are enough reasons why the chainsaw does not start. To find out what exactly happened in your case, you need to remember the symptoms the day before. Perhaps before the chainsaw stopped starting, engine malfunctions were observed, power and performance decreased, and other breakdowns were also appropriate. Based on these technical symptoms, it is necessary to begin the search. If you don’t know where to start, then the diagnostics should be carried out in order, as described in the material.

Fuel and air filters. Checking their serviceability

If the fuel or air filter is clogged, the chainsaw will also not be able to start. First you need to check the health of the air filter, which is located in a plastic case. Chainsaw air filter is very often clogged, therefore it is recommended to clean it before use. You will need to use a compressor for cleaning. If the air filter on the chainsaw is clogged with sawdust and shavings, then the engine will not start hot. Air does not enter the carburetor, so only excess fuel is supplied to the cylinder, which causes the spark plug to flood.

The case of a clogged air filter on a chainsaw is very interesting. If it is clogged, it usually starts up on a cold chainsaw, but as soon as the air damper opens to supply air, the engine immediately stalls after warming up. It will not start at all on a hot chainsaw with a clogged filter, or it will start and immediately stall. When diagnosing the air filter, you need to pay attention to the damper, through which the air supply is limited. Make sure the shutter moves freely when you push the lever to close and open.

  • If the damper does not close, then the attempt to start the chainsaw on a cold one is unsuccessful.
  • A similar situation is when the chainsaw is hot. If the engine starts up cold, but stalls when warming up, then this may be due to the fact that the damper is stuck in the closed position
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As you can see, not only the start of the chainsaw engine depends on the serviceability of the air filter and the damper, but also its proper operation.

In addition to the air filter, the cleaning element responsible for cleaning the fuel mixture can also become clogged. This filter is located in the chain saw tank and prevents small grains of sand from entering the carburetor. Like the air filter, the fuel cleaner also needs to be cleaned. Cleaning is done by replacing the old filter with a new one. The service life of this element depends on various factors, and first of all, on the quality of the gasoline and oil used. If you pour fuel into the tank in windy weather, then the probability of sand grains entering the tank is 100%.

Depending on the model of the chainsaw, the principle of replacing the fuel filter may differ. However, even a beginner can cope with this procedure, since it is not difficult, and only requires adherence to the sequence of actions.

Fuel quality

It all depends on you. Read the instructions, read what quality gasoline is required for the normal operation of the saw, and do not save on the power of this mechanism. Its gasoline consumption is low, and fuel with a low octane number will quickly “kill” it.

The reasons

In general, there should be no problems with new equipment., since all its parts and elements are in perfect factory condition and have not been used by anyone before you.

The first and the main cause of the startup problem is that you are not following the operating instructions. If the instructions are followed, the problem may lie in the oil-gasoline mixture that you prepared in the wrong proportions. The third the reason why you cannot start a new instrument is a technical malfunction or a manufacturing defect.

Ignition system

Also known as ignition unit, this element is responsible for the electrical generation of the incendiary spark. If the electrodes on the spark plug can be pulled closer together, the unit cannot be repaired. It is simply replaced with a new one. To check for a spark, remove the spark plug, replace the tip and run the saw with no load. If the spark does not skip even after the electrodes come close, contact the service center. There, your saw will be fitted with a new ignition system.


Filters tend to clog and lose bandwidth. To check the fuel filter, disconnect the fuel hose from the carburetor and pump the gasoline mixture. If it comes in an even stream, the filter is in order. If it starts to drip or flow in a thin stream, the filter is clogged. It’s almost useless to clean it.

Better change the cartridge to a new one. As for the air filter, it clogs up if you cut something very fragile or dusty. Take out this element very carefully so that debris that has settled on it does not get into the carburetor. After removing, rinse, clean and dry, then gently put back in place.


Custom cleaning outside the service center is of poor quality. If you gave the tool to a familiar craftsman for cleaning, but after returning it did not manage to start it, the reason lies in residual dirt. You can take the saw for a professional cleaning, or you can do it yourself.

Start by draining the fuel / lubricant mixture. Then dry all parts and, if possible, clean off carbon deposits from them with files. Disassemble the saw into hoses, cylinders and valves. Disassemble the carburetor on a separate work surface. Replace the fuel filter, wash and reinstall the air filter. Wash all parts in warm soapy water and blow dry. Then collect everything in reverse order and try starting. He must be successful.

Chainsaw mechanisms do not work: reasons and solutions

You start the saw in different conditions. It can be hot, cold, worn out or new, and each of these cases requires a different approach.