Stihl 170 chainsaw will not start

One of the reasons why the muffler can clog is the use of a fuel mixture with an excessive amount of oil (the amount of oil is more than the manufacturer recommends), and the use of either oil that is not intended for two-stroke engines or low-quality oil..

Cylinder-piston group. Malfunctions of the cylinder-piston group are among the most serious. This is the worn out cylinder and piston, scratches and scuffs on their surfaces, wear or sinking in the grooves of the piston rings, wear on the crankshaft bearings. Most of these malfunctions lead to a drop in cylinder pressure and, as a result, to the inability to start the engine, or its inability to deliver full power. There are several ways to assess the state of the cylinder-piston group (CPG).

You can remove the muffler and look through the opened window, in which part of the side surface of the cylinder is visible. Despite the limited review, a general idea of ​​the state of the CPG in this way can still be obtained.

It is useful to measure the compression in the engine, which is informative enough regarding the condition of the parts of the CPG. The operation is carried out using a compressometer installed in the candle hole.

The crankshaft is turned using an electric motor (drill) with a flexible shaft or manually with a starter, while controlling the pressure on a pressure gauge. There is no spark in the chainsaw, no spark in the chainsaw, ignition coil replacement there is no spark on the chainsaw. No sparks chainsaw. The latter for a working chainsaw should be at least 8-9 atm (0.8-0.9 MPa). With its decrease, the engine power also decreases. At a pressure of 5 atm, the engine may work, but only at idle.

It is possible to accurately assess the state of the CPG only by completely disassembling the engine – by disconnecting the crankcase from the cylinder and removing the piston. If the latter has seizures, chips or deep scratches, it must be replaced. With regard to the cylinder, if the surface is worn out or damaged, it is possible to bore it to the repair size. The reason for low compression may be wear or coking of the piston ring. A serviceable ring should be clean from carbon deposits, sit freely in the piston groove and press tightly against the inner surface of the cylinder.

Typical Stihl chainsaw breakdowns

Owners of the Stihl 180 chainsaw unanimously recognize it as a good and reliable technique. But they also name several problems that most often occur with this chainsaw:

  • Leakage of chain oil. Because of what: at the junction of the hose from the oil tank and the oil pump, the tightness is broken. As a result, the pump draws air instead of oil. How to fix: disassemble the chainsaw for details. The hose can be replaced or simply re-seal with silicone adhesive.
  • Chainsaw will not start. Because of what: the valve, designed to equalize the pressure in the gas tank during fuel production, is clogged and does not perform its function. Vacuum forms inside the gas tank, which prevents the fuel supply. How to eliminate: open and close the gas tank cap, ventilate the combustion chamber. Remove and dry the candle. Clean the breather itself with a thin needle.
  • The candle needs to be restored. If it has not yet worked out its useful life, you can fix it yourself. Be sure to remove all remaining fuel from the tank first. Remove the candle and leave it outdoors in a dry place out of direct sunlight. The candle will dry for about a day, or at least 12-16 hours. Then you can put it back in place. Important: do not try to ignite the candle. Such advice can be found in some outdated reference books, but for modern models, calcining will simply ruin the part..
  • First emergency aid if your Stihl chainsaw is out of order. Try these tips – they work most of the time. If not, read on. We will consider possible problems in more detail..

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Checking the spark on the spark plug and eliminating the causes.

The first step in looking for reasons why your gasoline saw won’t start is to check the spark on the spark plug. There are many factors that affect the performance of this element. However, the main ones at the initial stage of instrument troubleshooting are:

  • Incorrect carburetor adjustment;
  • The presence of more than it should be, the amount of oil in gasoline;
  • Clogged air filter.

All of them contribute to the formation of carbon deposits on the spark plug electrodes. In 50 cases out of 100, the saws do not start on a cold one due to the absence of a spark due to carbon deposits on the electrodes and their corrosion. As a result, the gap either decreases or increases..

Checking the spark plug with an idle chainsaw

It is quite easy to check for a spark. This will require:

  • Remove the tip of the high-voltage wire;
  • Unscrew the candle;
  • Put the tip back on;
  • Lean the candle with a skirt against the cylinder;
  • Start with a starter.

If a good spark is observed between the electrodes at the time of starting the engine of the chainsaw, then everything is in order with the ignition unit. If it is not there, then it is worth cleaning the element itself and checking the gap of the electrodes. If necessary, use a special probe to adjust the distance between the contacts.

For candles from different manufacturers, the distance between the electrodes may fluctuate. For some, it may be equal to 0.5 mm. Others have 0.2 mm. Therefore, carefully study the manufacturer’s recommendations..

There may be no spark on the spark plug for other reasons. Of the main faults affecting the poor start of the chainsaw and the unstable operation of the internal combustion engine at idle, from which the tool can stall, the following can be attributed:

  • Overflow of the spark plug channel with fuel;
  • Lack of contact between the high-voltage cradle and the tip of the candle;
  • Failure of the ignition unit.

How to start a cold chainsaw if the spark plug channel is constantly flooding with gasoline? To eliminate the problem while starting the tool, you can use the following algorithm:

  • Unscrew the candle with a special key;
  • Wipe it with a clean and dry cloth;
  • Dry for 20 … 30 minutes;
  • Remove carbon deposits with a file and adjust the gap between the electrodes;
  • Drain the remaining fuel from the spark plug channel and dry it;
  • Collect everything and try to start the mechanism.

CHAINSAW WON’T START STIHL MS 170

As a rule, these measures are enough to start the chainsaw and get the job done. However, this extreme measure does not eliminate the main reason why the engine does not start or stalls – improper operation of the carburetor, which needs fine adjustment..

If there is no spark and poor contact of the high-voltage cradle with the spark plug tip, check the connection. The check can be carried out using a conventional tester. If a defect is found and it is eliminated, the chainsaw should start without any problems.

If the check showed that the contact is reliable, and the saw does not start further, look for the cause in the ignition unit. As a rule, a faulty unit cannot be repaired and restored. A complete replacement is required here..

stihl, chainsaw, start

NO SPARK IN CHAINSAW, replacement of the ignition coil / NO SPARK IN THE CHAINSAW, ignition coil replacement

This video examines the breakdown of the ignition coil, its replacement and starting the chainsaw. And also watch my.

Chain brake

Why the chainsaw won’t start?

The biggest nuisance that can happen is when the chainsaw won’t start at all. In this case, it is not clear what is the cause of the breakdown. There are several typical situations, and most likely one of them is your case:

  • The chainsaw won’t start because there is no spark. To achieve ignition, first pull out and check the spark plug – it may be flooded. Then provide air access to the gas tank – to do this, simply open its lid, wait 5 minutes and close it again. Finally, direct the cool air flow (ventilation) towards the combustion chamber. If the problem is small, then you can assume that you have already solved it. The chainsaw will start without problems.
  • The chainsaw will not start, although there is a spark. Perhaps the candle is completely out of order and needs to be replaced. At the same time, check the condition of the air filter. All these details affect the pressure in the gas tank. Under normal conditions, a valve called a breather is responsible for maintaining even pressure. A faulty spark plug and / or air filter will lead to its contamination. Accordingly, when the gasoline is produced, the pressure is broken, the fuel does not flow on time, and a vacuum chamber forms in the gas tank. This seems like a big problem, but in practice, the solution is to simply remove the dirt plug that interferes with the breather. Long, thin needle – the right tool for cleaning the breather and restoring the performance of your chainsaw.
  • The chainsaw will not start, although it did start yesterday. Make sure there is enough lubricant on the chain. It may not come in the right amount due to a plug in the oil hose. Or vice versa, a crack has formed in the hose and oil flows out before reaching its destination..
  • The chainsaw starts up briefly and immediately stalls. This symptom is similar to a malfunctioning carburetor. But before you repair it, make sure that the problem is not the same as described in the previous paragraph, and that the breather is not the fault. Disconnect the fuel hose from the carburetor. See if Stihl Chainsaw Gasoline is leaking? Try to clean the carburetor, it may well be clogged.
  • The chainsaw starts up and soon shuts down spontaneously. Make sure the cylinder is intact. During self-diagnosis of the saw, you should be alerted by cracks, chips and other similar defects.
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As you can see, in most cases, if a Stihl chainsaw breaks down, you can fix the problem yourself. But don’t be too arrogant! If you did not find a suitable description in this article, then it is better to contact the service center..

Professional craftsmen will surely diagnose why the Stihl chainsaw does not start, and will professionally correct it. Let your technique work without problems!

By the way, if you need to repair a Partner (Partner 350) chainsaw, which is as popular as Stihl, then you can read about it in the next article.

And for those who like to know more, we suggest that you familiarize yourself with the video on repairing the Stihl chainsaw

Checking the breather and cleaning it.

The breather is another element, from the improper operation of which the chainsaw may not start or stall during the sawing process. This element is located on the fuel tank cap in the area of ​​the air hole. This is a kind of valve that does not allow gasoline to flow out and equalizes the air pressure required for the free flow of fuel into the carburetor.

If the breather is dirty, the working chainsaw stalls, and when it starts, it refuses to start. The thing is that air stops flowing through the hole. As a result, a negative pressure (vacuum) is created inside the fuel tank, which prevents the flow of gasoline to the carburetor..

Defining the problem is pretty straightforward. Disconnect the fuel hose from the carburetor and see what happens to the gasoline. If it flows freely in a good trickle, then everything is in order with the breather. If it is absent or it flows weakly and intermittently, then the reason is identified – the breather is clogged with dirt. You can solve the problem by cleaning the air hole with a regular needle or a powerful jet of compressed air..

Chainsaw outlet check.

One of the reasons that a chainsaw does not start well may be a clogged exhaust channel or its muffler. At the same time, a drop in power is noted in the process of sawing sawn timber and logs. This is most often due to resinous deposits on the spark arrestor or muffler channel, which are formed during the combustion of a poor-quality mixture of gasoline and oil, which impede the removal of exhaust gases.

Resonator clogged with carbon deposits can cause poor starting of the gasoline saw.

Eliminate the cause of the poor start of the chainsaw, in this case, you can remove the accumulated combustion products. To do this, perform a number of manipulations:

  • Remove the muffler by unscrewing the screws;
  • Remove the cooling panel and gasket;
  • Remove the spark arrestor;
  • Disassemble the resonator housing;
  • Wash all elements from carbon deposits with a detergent;
  • Let them dry completely;
  • Collect everything in reverse order;

To prevent dust and sand from getting into the cylinder when cleaning the muffler, cover the outlet of the chainsaw engine with a clean rag..

Replacing the crankshaft bearings

It is better to replace the crankshaft bearings in a specialized service, because when replacing, you will need to completely disassemble the Stihl 180 chainsaw and remove all its main components.

Without some experience or at least the skills of repairing similar chainsaws, it will not work to replace the crankshaft bearings efficiently.

So, we figured out the absence of a spark, but what to do if there is a spark, and there is no answer to the question of why the Stihl 180 chainsaw does not start. The reason may be hiding in the fuel system..

Ignition coil problems

Fuel does not flow

This type of malfunction, like the others, has its own characteristic symptom. It consists in the fact that the working spark plug, on which there is a spark, will be absolutely dry. You can check suspicions of a lack of fuel supply using the following algorithm.

Stihl 180 fuel system malfunctions

In some cases, as a rule, if there is a spark on the spark plug, when examining it, you can notice that it has a wet coating, this indicates an excessive supply of fuel to the combustion chamber and, as a consequence, the impossibility of igniting the fuel mixture..

Checking the pulse from the engine crankcase

The fuel pump on the Stihl MS 180 chainsaw is installed directly in the carburetor and works under the influence of impulses from the crankcase of the Stihl 180 chainsaw. The impulse is transmitted through a pulse channel in the rubber pipe connecting the cylinder to the carburetor.

Clogging of the channel is fraught with the appearance of problems with the supply of fuel or its complete absence. To check the pipe, it is necessary to remove the air filter housing and the carburetor, and then check the channel for clogging with a thin metal wire.

All rubber parts of the Stihl 180 chainsaw should be periodically inspected for cracks. If defects are found, the defective elements must be replaced with new ones..

Another reason associated with the absence of an impulse in the pipe channel is the depressurization of the engine crankcase, which results in air leakage from it and a decrease or complete cessation of its supply to the fuel pump. The result of depressurization is a partial or complete loss of the fuel pump performance. To check the tightness of the crankshaft oil seals, and indeed the crankcase of the Stihl 180 chainsaw, a special vacuum gauge is used, and since it is a special-purpose tool, it is mainly available only in service centers. The question arises, what to do?

Read more:  How to Start a Stihl 180 Chainsaw Properly

You can check the impulse supply using a syringe on the engine with the carburetor removed. You will need to draw a little oil into the syringe to lubricate the engine and squeeze it into the impulse channel of the pipe, then pull the starter. If the impulse does not pass, the oil will remain in the channel and you should look for the cause deeper, disassemble the engine and check the oil seals. If the oil is squeezed out of the channel, then the problem may be hidden in the fuel pump itself..

Algorithm for checking for lack of fuel supply

  • Unscrew the candle;
  • Using a syringe, pour 1-2 cubes of the fuel mixture into the spark plug hole;
  • Install the candle and put on the cap of the high-voltage wire;
  • Set the engine control lever to the hot start position;
  • Pull the starter several times.

If, after several movements with the starter, the Stihl 180 chainsaw started up and immediately stalled, then the suspicions in the lack of fuel supply were confirmed and you can proceed to further diagnostics of the fuel line.

Fuel line diagnostics

As a rule, the diagnosis of the fuel supply system begins with checking the condition of the fuel filter. To do this, unscrew the tank cap and, using an aluminum wire bent at the end, remove the fuel hose from the tank, with a filter at the end.

Having taken out and dismantled the filter, you can try to blow into it, if air does not flow, then the problem has been found. If everything is in order, then you need to check the system for blockage..

To check the fuel supply hose, you must disconnect it in the place where it connects to the carburetor, and then blow into it. The clogged hose can be cleaned mechanically, if this is not possible, replace with a new one..

In the event that the supply hose and the fuel filter are normal, and the fuel supply is not observed, the reason may be hidden in a malfunction of the air pulse to the fuel pump..

Determine the availability of fuel and its supply.

First you need to make sure that there is a fuel mixture in the tank of a chainsaw that does not want to start, and it regularly enters the carburetor. With a full tank, we check how the mixture is fed through the gas line. We disconnect the fuel system pipe from the carburetor and try to pump it up. In the case of a complete order, when pumping up, gasoline will be supplied in jerks in accordance with the norms set by the manufacturer. Poor or no fuel supply may result from:

  • The fuel supply channel is clogged;
  • Debris-clogged fuel filter.

Often the reason for a poor start of the chainsaw can be a tank that is too full. In this case, you should pay attention to the presence of smudges under the saw case cover. If present, see the connection of the gasoline feed pipe to the carburetor. Most often, it is squeezed out by pressure when the tank cap is screwed on, which is filled under the very neck, which prevents the engine from starting.

stihl, chainsaw, start

The quality of the fuel mixture can also be one of the reasons why the chainsaw does not start. If, after completing the work, the remaining gasoline is not drained, and the tool is left for long-term storage (more than 2 weeks), then the processes of resinification and polymerization of the components will begin to occur inside the tank. What can cause carbon deposits on the piston, rings and cylinder liner. Therefore, always prepare the mixture only in the required amount before work..

Checking the breather and cleaning it.

The breather is another element, from the improper operation of which the chainsaw may not start or stall during the sawing process. This element is located on the fuel tank cap in the area of ​​the air hole. This is a kind of valve that does not allow gasoline to flow out and equalizes the air pressure required for the free flow of fuel into the carburetor.

If the breather is dirty, the working chainsaw stalls, and when it starts, it refuses to start. The thing is that air stops flowing through the hole. As a result, a negative pressure (vacuum) is created inside the fuel tank, which prevents the flow of gasoline to the carburetor..

Defining the problem is pretty straightforward. Disconnect the fuel hose from the carburetor and see what happens to the gasoline. If it flows freely in a good trickle, then everything is in order with the breather. If it is absent or it flows weakly and intermittently, then the reason is identified – the breather is clogged with dirt. You can solve the problem by cleaning the air hole with a regular needle or a powerful jet of compressed air..

Chainsaw outlet check.

One of the reasons that a chainsaw does not start well may be a clogged exhaust channel or its muffler. At the same time, a drop in power is noted in the process of sawing lumber and logs. This is most often due to resinous deposits on the spark arrestor or muffler channel, which are formed during the combustion of a poor-quality mixture of gasoline and oil, which impede the removal of exhaust gases.

Resonator clogged with carbon deposits can cause poor starting of the gasoline saw.

Eliminate the reason for the poor start of the chainsaw, in this case, you can remove the accumulated combustion products. To do this, perform a number of manipulations:

  • Remove the muffler by unscrewing the screws;
  • Remove the cooling panel and gasket;
  • Remove the spark arrestor;
  • Disassemble the resonator housing;
  • Wash all elements from carbon deposits with a detergent;
  • Let them dry completely;
  • Collect everything in reverse order;

To prevent dust and sand from entering the cylinder when cleaning the muffler, cover the outlet of the chainsaw engine with a clean rag..

Identifying and eliminating obvious chainsaw malfunctions.

To determine the reason why the chainsaw does not start or stalls when starting, it is necessary to troubleshoot the tool. The essence of the procedure is to consistently inspect the condition and operation of the main working elements of the saw motor. At this stage, we check:

  • Spark plug present;
  • Fuel supply;
  • Filter status;
  • The operation of the breather of the stalling unit built into the fuel cap;
  • Discharge duct function.

to the content

Checking the condition of the fuel and air filters.

If everything is in order with the fuel quality, the chainsaw engine may not start due to clogged fuel and air filters. To diagnose these elements, it will be necessary to perform a number of manipulations associated with their dismantling..

For the fuel filter:

  • Disconnect the gasoline supply channel from the carburetor;
  • Pump up fuel.

If there is little or no pressure in the branch pipe, disconnect the filter. Before this, free the tank from the mixture and remove the filter element itself. Dismantling is done with a wire hook. A clogged replacement cartridge that causes a poor starting of the chainsaw engine can be cleaned, but it is best to replace it with a new one. When using the tool in dusty conditions, it should be cleaned on a regular basis..

A clogged air filter can cause the chainsaw engine to run erratically, making it stalling or difficult to start. Dust and dirt deposited on the adsorbent material impede the flow of air into the system, make the fuel mixture so rich that it will sometimes be difficult to start the tool.

Checking the air filter is one of the first steps in finding the cause of a poor start.

Care should be taken when removing the air filter, as dust accumulated on the surface of the saw during operation can enter the carburetor. And this is fraught with more expensive repairs. After detaching the cartridge, thoroughly clean it of accumulated dirt and rinse it with the addition of detergent. Dry the element and put it back in place just as carefully..

Read more:  Stihl Saw Won'T Start

Finding reasons why the chainsaw won’t start

Amateur and professional chainsaws are complex devices. The service life of their two-stroke engines, components and assemblies has its own limitations. For this reason, quite reliable and expensive tools, along with cheap Chinese units, periodically fail and refuse to start. The situation when the chainsaw does not start or stalls is not very pleasant and sometimes confuses the user. How to identify and correct a malfunction by returning the instrument to work.

  • Identifying and eliminating obvious chainsaw malfunctions.
  • Checking the spark on the spark plug and eliminating the causes.
  • Determine the availability of fuel and its supply.
  • Checking the condition of the fuel and air filters.
  • Checking the breather and cleaning it.
  • Chainsaw outlet check.
  • What to do if the chainsaw won’t start further?

Checking the spark on the spark plug and eliminating the causes.

The first step in looking for reasons why your gasoline saw won’t start is to check the spark on the spark plug. There are many factors that affect the performance of this element. However, the main ones at the initial stage of instrument troubleshooting are:

  • Incorrect carburetor adjustment;
  • The presence of more than it should be, the amount of oil in gasoline;
  • Clogged air filter.

All of them contribute to the formation of carbon deposits on the spark plug electrodes. In 50 cases out of 100, the saws do not start on a cold one due to the absence of a spark due to carbon deposits on the electrodes and their corrosion. As a result, the gap either decreases or increases..

Checking the spark plug with an idle chainsaw

It is quite easy to check for a spark. This will require:

  • Remove the tip of the high-voltage wire;
  • Unscrew the candle;
  • Put the tip back on;
  • Lean the candle with a skirt against the cylinder;
  • Start with a starter.

Fix a Stihl chainsaw that doesn’t start, model MS 170

If a good spark is observed between the electrodes at the time of starting the engine of the chainsaw, then everything is in order with the ignition unit. If it is not there, then it is worth cleaning the element itself and checking the gap of the electrodes. If necessary, use a special probe to adjust the distance between the contacts.

For candles from different manufacturers, the distance between the electrodes may fluctuate. For some, it may be equal to 0.5 mm. Others have 0.2 mm. Therefore, carefully study the manufacturer’s recommendations..

There may be no spark on the spark plug for other reasons. Of the main faults affecting the poor start of the chainsaw and the unstable operation of the internal combustion engine at idle, from which the tool can stall, the following can be attributed:

  • Overflow of the spark plug channel with fuel;
  • Lack of contact between the high-voltage cradle and the tip of the candle;
  • Failure of the ignition unit.

How to start a cold chainsaw if the spark plug channel is constantly flooding with gasoline? To eliminate the problem while starting the tool, you can use the following algorithm:

  • Unscrew the candle with a special key;
  • Wipe it with a clean and dry cloth;
  • Dry for 20 … 30 minutes;
  • Remove carbon deposits with a file and adjust the gap between the electrodes;
  • Drain the remaining fuel from the spark plug channel and dry it;
  • Collect everything and try to start the mechanism.

As a rule, these measures are enough to start the chainsaw and get the job done. However, this extreme measure does not eliminate the main reason why the engine does not start or stalls – improper operation of the carburetor, which needs fine adjustment..

If there is no spark and poor contact of the high-voltage cradle with the spark plug tip, check the connection. The check can be carried out using a conventional tester. If a defect is found and it is eliminated, the chainsaw should start without any problems.

If the check showed that the contact is reliable, and the saw does not start further, look for the cause in the ignition unit. As a rule, a faulty unit cannot be repaired and restored. A complete replacement is required here..

What to do if the chainsaw won’t start further?

If the initial inspection did not give anything or the defects were eliminated during the search, and the chainsaw does not start further, then you need to look for more serious reasons. It is best to identify and eliminate such breakdowns in a service center. However, with experience, you can find and eliminate them yourself. What to diagnose and check?

  • Compression in the cylinder;
  • Compression in the crankcase;
  • Carburetor operation.

In the first case, checking the compression in the cylinder will allow you to find out the state of the cylinder-piston group (CPG) of a chainsaw that does not want to start cold. For this you need a compressometer. The device is screwed into place of the spark plug and the engine is idle. Measurement of readings allows you to judge the state of the CPG. In the absence of a compression gauge, the compression in the cylinder can be determined offhand as follows:

  • Place your finger on the candle hole;
  • Try to start the chainsaw engine..

By placing your finger on the spark plug hole and pulling the starter, you can check the compression in the cylinder.

If you feel that your finger is pulling strongly into the candle channel, then everything is in order with the compression. The absence of a vacuum in the chamber indicates a malfunction. The cylinder-piston group needs a more detailed inspection, which will give an idea of ​​the condition of the piston and cylinder, piston rings and bearings.

The chainsaw may not start on a cold one due to the lack of compression in the engine crankcase. The main reason for this is damage to the gasket placed between the cylinder and the crankcase. It is quite easy to detect the lack of compression:

  • Disconnect the upper tube from the carburetor;
  • Pour gasoline into an ordinary cork;
  • We immerse the removed tube in the fuel;
  • We pull the starter several times.

If the fuel is sucked from the cap when starting the chainsaw starter, then everything is in order with the compression. If not, see the gasket.

If the fuel is drawn in, then everything is in order – the gasket is intact. Otherwise, you will have to purchase a repair kit and replace it. How to do this watch the video why the Chinese chainsaw does not start:

Starting the tool can be complicated by improper operation of the carburetor or its breakage. It often happens that during the sawing process, the fastening screws are loosened and air is sucked into the cylinder. Check that the carburetor is securely fastened. Inspect it for fuel leaks. There can be a lot of reasons for the malfunction. It is possible to pinpoint the malfunction, eliminate it and fine-tune the carburetor only in a service center..

After going through the step-by-step troubleshooting of the chainsaw engine, you can find the malfunction, fix it yourself and successfully start your working tool. Do not take on jobs that you are not sure about. Entrust the troubleshooting to specialists from the service center.