Why a Husqvarna chain saw won’t start. Ignition coil

Why gasoline does not flow into the carburetor of a chainsaw

If properly handled, chainsaw malfunctions are rare and can be fixed quickly if the owner knows where to look for the cause.

If the situation arises when the chainsaw does not start, it is important to properly diagnose, determine the direction in which to look for the fault. It is not a good idea to use a tool that does not idle, as this indicates the presence of air leaks in the engine and can lead to serious problems. If the experience in the repair of chain saws is not enough, it is better to turn to a specialist who will save your time and nerves.

Yet there is no definitive answer to the question of why the chain saw fails to start. This tool is basically an ordinary two-stroke internal combustion engine. Four conditions are necessary for its normal operation: fuel, air, spark and lubricant.

For the preparation of air-fuel mixture is responsible carburetor, the air from dust clears the filter, the spark creates the ignition unit and the spark plug, and the lubricant is in the gasoline.

The reasons why the chainsaw refuses to start should be looked for one by one, starting with simple ones and moving on to more complex ones. Anyone who immediately rushes to disassemble the carburetor when the chainsaw does not start when hot, greatly risking. It is better to have this assembly repaired and adjusted in a specialized workshop rather than by hand.

By the way, some chainsaw manufacturers, in order to save users from getting into the carburetor to change the fuel mixture, make the jets unregulated.

My Husqvarna Chain Saw Won’t Start When Hot

To keep your chainsaw working reliably you need to pay special attention to fuel. If the fuel mixture is incorrectly mixed, even a reliable Husqvarna will not start. In this case the owner will look for the cause of malfunction anywhere, but not in the fuel. To avoid this factor, you should always prepare a fuel mixture of high-quality gasoline and that brand of oil, which is specified in the manual.

It should be made in such quantity that in 1-2 weeks it will work out completely. If you keep it in the can for a month, the gasoline will lose its octane properties and you will have problems with the saw’s operation.

Quite often malfunctions of chainsaws occur because the spark plug is flooded with gasoline at startup. This problem can be solved by unscrewing and drying the spark plug (without burning it)!) In this case, the excess fuel is drained through the spark plug hole, and then make a 20-30 minute break, then put the plug in place and repeat the start. A good owner always has new plugs in stock, in order to exclude this part from the list of suspects while searching of faults.

Lack of spark is often caused not only by a faulty spark plug, but also by poor contact between the spark plug lug and the high-voltage wire. If this connection is not suspicious when checked, but the spark does not appear when you turn on the starter. the electronic ignition unit is to blame. This assembly is not repairable, but replaced with a new one.

Remember that the spark plug inspection is an important piece of information. If it is dry, it means that the cylinder does not receive fuel and you need to check the whole chain of its supply, starting from the carburetor. Black carbon deposits indicate improper carburetor adjustment, feeding too much fuel into the mixture, or oil overflowing into the gasoline.

If your chain saw starts and stops when you hit the gas, it is an indication of a bad fuel supply. The cause may be a clogged fuel filter or carburetor nozzle. The first unit can be checked and cleaned very quickly, but in the second case, it is better to trust the professionals.

Disassembling and cleaning a chainsaw carburetor requires experience and care. That’s why it’s usually only done by those owners who have already done it many times and successfully.

Attention should also be paid to the air filter so that you don’t look for the cause of chainsaw malfunctions in the wrong direction. If it is clogged with dust, then you can’t count on easy starting and stable operation.

Each chainsaw model has its own characteristic and easily correctable faults. Therefore, do not rush with disassembly and repair, and it is better to read the reviews of owners on the forums. For example, gasoline STIHL saws can not start due to the banal clogging breather.

This valve equalizes the pressure in the gas tank as fuel is released. When it is clogged, a vacuum forms in the tank and fuel stops flowing into the carburetor. This disease is treated by cleaning the breather valve with an ordinary sewing needle.

It is not difficult to exclude the breather plug from the list of suspects. To do this, disconnect the fuel hose from the carburetor and see if fuel is leaking from it. When the gasoline flows in a full stream. the breather is clean, if the fuel does not flow from the gasoline line or flows very slowly, then the cause of the malfunction is established.

Many new STIHL chain saw owners are afraid of the idle speed increase after the first tank of juice has been pumped. Specialists consider this behavior to be normal and an indication that the engine and carburetor are running in good condition. So don’t rush to a service, but just turn down the engine speed a bit with the idle speed screw.

If you notice a drop in power and the chainsaw idles, don’t forget to check the muffler, it could be clogged with tarry exhaust fouling. Cleaning the exhaust port and the muffler removes these problems.

Especially unpleasant for the owner, when all possible causes seem to be eliminated: a new serviceable spark plug is installed, the carburetor is carefully and correctly cleaned, the fuel is normal, but the chainsaw still does not want to start.

husqvarna, chain, start, ignition, coil

In this case, you need to look into the cylinder-piston group. Visual inspection of the cylinder and piston in this case helps to find the cause. If there are obvious chips or scuffs on them, the saw will work normally only after replacing these assemblies. correct the problem by re-boring the cylinder for a new piston of known repair size.

How to restore operation

The machine won’t start when it’s hot So the course of action depends on when the saw stops:

  • Immediately after starting. too much oil in the fuel mixture. In this case the octane rating of the gasoline decreases and the saw only works on suction.
  • When tilted. not enough fuel in the tank. This problem is the easiest to solve. just refill the gasoline.
  • Starts with difficulty and immediately cuts out. spark plug is encrusted or clogged. Unscrew and flush out the parts. If the tar is already hardened, heat the spark plug with a lighter and then clean it. But be careful not to damage the pins. Then wash the spark plug in petrol and dry it. Dry the cylinder at this time: pull the starter rope several times. Replace the spark plug.
  • At idle revs. the silencer is clogged. Take it off the tool, wash it with grease or gasoline, dry it and put it back. The saw also stops at idle speed if the gap between the spark plug and the wire is too big. It can be adjusted at idle for solving the problem.

Each of these causes appears at a certain stage of the tool’s life.

  • Immediately after starting. carburetor settings are off. It can be adjusted at idle speed with the L and H bolts.
  • At maximum rpm. fuel filter or breather is clogged. Filter must be replaced. Clean the breather plug with a fine needle.
  • If loaded, the air filter is clogged. Take it out, blow out to eliminate dust. If heavily soiled, rinse and dry thoroughly.
  • Runs only on the suction. faulty gasoline pump. Part should be removed and checked for fuel leakage. If gasoline leaks, replace the gasket or replace the pump completely.
  • Stops after warming up. magneto malfunction. In most tool models, this part is not repairable, so it must be replaced.

How to tune a chainsaw

In the process of repairing the Husqvarna chainsaw with their own hands reveal some malfunctions that occurred as a result of improper ignition adjustments and carburetor settings.

Husqvarna 371 XP won’t rev up, back fires, and stalls. Went through whole saw, bad ignition module

The mechanism is responsible for the revolutions of the motor and is tuned for operation with the right conditions in mind:

Factory default settings of Husqvarna chainsaw carburetor are set at the time of testing for productive operation.

The unit has 3 adjustable areas:

To adjust the chainsaw, after running-in perform adjustment of the carburetor: first dealing with jig “L”, then the idle speed screws “T” and “X”. Turning “L” and “X” clockwise makes the air-fuel mixture worse, turning them counterclockwise makes the mixture richer. Turning the “T” screw clockwise increases idle RPM.

Repair of the carburetor is performed by a specialist.

How to dilute gasoline for your Husqvarna chainsaw

For productive work and longer life at high power observe the proportion of oil and gasoline for gasoline chainsaw, measuring with measuring cup the ratio of the ingredients of the fuel mixture. When mixing even a small amount of gasoline, a small inaccuracy will affect the quality of fuel.

Use quality gasoline with minimum octane number. RON 90. If the parameter is less than recommended, the engine starts knocking, which leads to its overheating and increased load on the bearings. If you work constantly at high RPM, choose gasoline with a higher index.

It is recommended to use 2-stroke oil.

husqvarna, chain, start, ignition, coil

To properly dilute gasoline for a chainsaw, use the following mixing scheme:

  • for engines with a cylinder displacement up to 80 cm³. 1:50 (2%), t.е. 5 liters of gasoline. 0.10 liters of oil;
  • for engines with a volume above 80 cm³. 1:33 (3%), t.е. 5 liters of gasoline, 0.15 liters of oil.

Husqvarna 137 chain saw does not start

This company is a very famous brand, so I would not advise to disassemble, repair and tune such equipment.Please call your Service Center and let them figure it out.

The spark plug should have an even brownish, or grayish tint when the mixture is normal.

Maybe you just “sucked” the cylinder with gasoline, then the spark plug will be wet.

Pull the starter rope a few times.To let the cylinder ventilate from excess gasoline.Blow it out, and then massage the spark plug body onto the cylinder, it’s better to do it in the shade, and see if there’s a spark.

Start the saw on the “suction” by pulling on the pull rod, pull the cord a few times until the “wail”.If it squeaks. unclog the choke and start without choke.

Does not help-then unscrew the screws “L” and “H” at 18 turns, in the cylinder will go more gasoline.

Start the engine and the carburettor will squirt some gasoline which might not be enough to start the engine.

Chainsaws and brushcutters of this make usually start well. Before you panic and immediately disassemble to the screws, you need to start with the simplest. Most often it is a problem with the fuel. It is necessary to mix gasoline and oil correctly and fill the tank. Don’t forget to move the choke lever to the “closed” position. Then you need to pull the starter cord a few times and the saw should start. Did not start? Assume “suction”.

Push the choke lever to “open” position, full throttle and pull the cord again. Sometimes the saw starts at this stage. If not, just walk around for a while, calm down, and start over. And only after the third round you need to start unscrewing the spark plug and everything else, if you have any experience of dealing with two-stroke engines, for example mopeds. If there is no experience, you need to turn to those who have.

In experienced hands, the saw will quickly come to life, and they will also teach you how to start it.

If the saw started, worked, the user is experienced, properly cared for, kept clean, he will immediately realize that something goes wrong and the saw requires serious repair.

A chainsaw is indispensable in the daily life of the owner. This tool is in great demand and popularity, because it helps to facilitate the work of a forester or gardener. Husqvarna is a popular company that has long been engaged in the production of quality tools, as well as equipment for further work in the garden.

and more often people buy a chainsaw Husqvarna 137 for use in private enterprises, households or forestry. Presented products are well proven in large-scale industrial construction.

The manufacturer offers its customers a wide and diverse range of products, but the main focus is the development of chainsaws. Husqvarna 137 saw is the most successful and high-quality model. It is easy to use, lightweight and economical. But it is also powerful enough to handle large amounts of work.

No hot starts on chain saw

In those cases when the chainsaw does not start on hot, it is necessary to carry out a visual inspection of all the main nodes of the chainsaw. Inspection should begin with the spark plug. Check the spark, inspect the surface of the spark plug electrode, these actions will help determine the direction in which to look for the problem.

Trouble in the ignition system

If when inspecting the spark plug, it is found that it is wet and spark formation on the contacts does not occur, it means that the problem should be sought in the ignition system, inspect the coil, check the gap between the flywheel and coil contacts. You can also check how firmly the spark plug boot is seated on the spark plug and the spark plug itself. Try to replace it with a new one.

Problems in the fuel system

If the examination reveals that there is a spark and the spark plug is dry, it means that the problems are in the fuel system. It is necessary to start check it with the fuel filter. Next, you need to inspect the fuel hose and its attachment to the carburetor, pay attention to fuel leaks from the carburetor and the presence of gasoline in the air filter housing. You should start removing a carburetor only if visual inspection did not determine the cause of failure.

A typical sign of a problem with the fuel system is that there is too much fuel in the cylinder. This is usually indicated by the spark plug being excessively wet and having a spark on the spark plug pins. In this situation, you need to turn the chainsaw so that the spark plug hole is pointing down. If you get gasoline leaking from the cylinder, it is because the chainsaw won’t start if the fuel overflows into the engine.

“Fills up” with fuel, sometimes due to improper carburetor adjustment, or its malfunction.

With the process of adjusting the carburetor, you can get acquainted with the example of Champion 254 saw, watching the video instructions.

Finding the reason why the chainsaw won’t start

Amateur and professional chainsaws are complicated devices. The battery life of their two-stroke engines, components and assemblies has limitations. For this reason, quite reliable and expensive tools on par with cheap Chinese units periodically fail and refuse to start. The situation when a chain saw won’t start or stops isn’t very pleasant and sometimes it puts the user at a loss. How to determine and fix the problem and get your tool working again.

  • Identifying and troubleshooting obvious chainsaw malfunctions.
  • Checking spark plugs and eliminating causes.
  • Detecting fuel availability and fuel supply.
  • Check condition of fuel and air filter.
  • Checking the breather plug and cleaning it.
  • Checking the chain saw’s exhaust port.
  • What to do if the chainsaw won’t start or will not start?

Your chain saw does not start

If the tool stalled and does not start, it is worth checking the fuel in the tank first. Strange as it may sound, but many people forget about it and when a similar situation arises, immediately try to repair the tool, which can lead to serious damage.

If you have turned off the saw and there is still gas in the tank, you need to look at how the saw was working before. During work at the last moment extraneous noise, rattle, ringing occurred, there was a loss of power or the tool stopped abruptly. All this allows you to preliminarily assess the situation.

The engine is stuck

Quite often there is a situation when the saw was working and suddenly stopped, the cause of which was jamming of the engine, which in turn was the result of burst piston skirt, crankshaft bearing failure, runout of the corkscrew ring of the piston pin or broken piston ring.

Jammed engine can easily be detected by pulling the starter cord. In the case when the starter does not turn, most likely it is jammed and further repair is possible only in the service center.

Fuel line breakage

When the chainsaw is running vibration occurs, which can cause damage or rupture of the fuel line of the chainsaw. If this occurs, the chainsaw will stall and cannot be started. To diagnose a malfunction, you need to inspect and determine the presence of fuel leaks.


Overheating of the engine while working may cause the chain saw to stall and not start. Overheating is dangerous enough as it can melt the piston in the cylinder and cause the engine to seize. At the first cases of overheating it is worth to perform diagnostics of the tool for the presence of extraneous air suction in the engine and carburetor adjustment.

husqvarna, chain, start, ignition, coil

Air suction, as well as incorrect carburetor adjustment, affects the maximum engine speed and lubrication, which in turn causes overheating and seizure of the tool.

Your chain saw won’t turn on hot

In those cases when the chain saw does not start when hot, it is necessary to carry out a visual inspection of all the main chain saw components. Start with the spark plug. Check the spark, inspect the surface of the electrode of the spark plug, these actions will help to establish the direction in which to look for the problem.

Trouble in ignition system

If upon inspection of the spark plug, it is found that it is wet and spark formation on the contacts does not occur, this means that the problem should be sought in the ignition system, inspect the coil, check the gap between the flywheel and the contacts of the coil. Also you can check how tightly the cap of the high-voltage wire sits on the plug, and the plug itself. Try replacing it with a new one.

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Problems in the fuel system

If inspection revealed that the spark is there, but the spark plug is dry, it means that there is a problem in the fuel system. Start with the fuel filter. Next, you need to inspect the fuel hose and its attachment to the carburetor, pay attention to fuel leaks from the carburetor and the presence of gasoline in the air filter housing. It is advisable to remove the carburetor only if a visual inspection did not identify the cause of the failure.

A typical sign of a problem with the fuel system is that there is too much fuel in the cylinder of the engine. As a rule, it is indicated by an excessively wet spark plug and the presence of spark on the spark plug pins. In this situation it is necessary to turn the chainsaw upside down so that the spark plug hole is directed downward. If there is petrol leaking from the cylinder it means that the reason that the chainsaw will not start is that the fuel is overflowing into the engine.

“Fills” with fuel, sometimes because of improper adjustment of the carburetor, or its malfunction.

With the process of adjusting the carburetor, you can get acquainted with the example of Champion 254 saw, watching a video instruction.

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