Stihl MS 250 - balanced chainsaw for agriculture

Setting up the carburetor model

The professional chain saw Stihl MS 250 requires carburetor adjustment in the following cases:

• when the engine is unstable at idle speed;
• in the case when the internal combustion engine starts and immediately stalls;
• with a sharp increase in the volume of fuel consumed;
• with a noticeable increase in vibration of a running engine.

Adjustment of the fuel unit is performed in the following sequence:

1. First, screws H and L on a chainsaw with a cold internal combustion engine must be tightened clockwise until it stops. After this, both screws must be turned 1 turn in the opposite direction;
2. Next, you need to start and warm up the chainsaw engine. The operator must then press and hold the throttle trigger. At the same time, by turning screw H, you need to achieve the maximum engine speed indicated in the instructions for the saw. They should be 10,000 rpm;
3. Then you need to adjust the operation of the saw chain. To do this, the standard LA screw must be turned so that the chain begins to rotate slowly. After this, the LA bolt will need to be turned 1/4 turn counterclockwise.

How to adjust the carburetor on a lawn mower

Before adjustment, you need to carefully clean the filters according to the technical maintenance instructions.

The upcoming adjustment of the lawn mower carburetor is done with your own hands using adjusting screws. There are three in total:

Right (L) – adjusting the fuel consistency for low speeds.

It is necessary to find the highest idle speed. To do this, slowly unscrew the screw (L) to the right and to the left.

To adjust, turn the screw a quarter turn, always counterclockwise.

Bottom (T) – is responsible for adjusting the engine at idle.

• clockwise – increase;
• counterclockwise – decrease.

For correct idle speed adjustment it is typical:

• stable operation of a cool motor;
• not over-revving a hot engine;
• there is a large supply of revolutions for the trimmer head;
• stable operation of the motor when changing position (sudden raising or lowering of the knife).

Left (H) – consistency adjustment at high speeds. (The screw is adjusted last).

The overall adjustment of maximum speed, engine power, temperature and gasoline consumption depends on the left screw (H).

Setting up the carburetor of the lawn mower with the last screw is done as follows:

1. Open the throttle to full, and at the same time give full throttle. Turn the screw clockwise until the speed drops (in this case, use your ear).
2. Turn the screw as slowly as possible counterclockwise until the motor runs unevenly.
3. Then turn back quite a bit, barely hearing measured, even work.
4. For a more pleasant implementation of abilities, it is more convenient to see the work of an experienced user:

It is interesting that, based on the beliefs of the video creator, the setting (its correctness) is determined by the color of the candle, and not just by the speed and stability of the engine.

The correct setting of the carburetor with your own hands in this case is the combustion of the fuel mixture without residue, the color of the spark plug should be light brown.

Technical characteristics of the Stihl MS 250 chainsaw

The Stihl chain saw in the 250th factory configuration features improved factory parameters that allow the model to cope with the most complex household and construction tasks.

Key features of garden tools include:

• ICE power – 2.3 kW/3.1 l. With.;
• chain rotation speed at idle/maximum speed – 2,800/10,000 rpm;
• fuel tank – 470 ml;
• recommended tire length – 35–40 cm;
• chain pitch – 3/8 “;
• weight including saw set – 4.7 kg.

When developing the Stihl MS 250 chainsaw, the manufacturer managed to achieve a low noise level when the engine is running. When operating under maximum loads, this parameter of the garden tool is 105 dB.

Clutch drum bearing

Another chainsaw assembly that is subject to high loads is the clutch drum (cup), which includes the chain drive drive sprocket. Although the clutch drum bearings only work at idle speed of the chainsaw (when the throttle is open, the drum rotates at the speed of the crankshaft), high loads are placed on it - so cage-type needle bearings or without an inner ring are used here. Such bearings require regular lubrication and, even with careful care, require periodic replacement - usually along with the drive sprocket.

For STIHL chainsaws of models MS 170 - 311, 390, 391, a proprietary clutch drum needle bearing with dimensions of 10 * 13 * 10 mm is used. Interestingly, the same size needle bearings are used in the Echo CS2600, 2700, 3050, 260TES, 270WES chainsaws, as well as the Shindaiwa 452S-15 and some Champion models. Compatible bearings are produced by the Oregon brand. In addition, the range of the well-known brand INA-FAG includes a needle bearing K101310 with the same dimensions, which is used as a replacement for branded products that are not always available in Russian regions.

Experts, a leading supplier of industrial bearings in Russia, note that for most branded bearings that are used in chain saws, it is easy to find equally high-quality and reliable analogues from leading Western brands - such as Timken, NTN-SNR or NSK

However, in order for them to work for the period allotted to them, it is important to follow the installation and dismantling technology, to prevent deformation and excessive heating when seating on the axle

• Stihl MS 170 / MS 180 / MS 180 C-BE / MS 181 / MS 181 C-BE / MS 193 CE
• Stihl MS 211 / MS 211 C-BE / MS 230 / MS 230 C-BE / MS 250 / MS 250 C-BE / MS 271
• Stihl MS 310 / MS 241 / MS 260 / MS 261 CM / MS 361 / MS 362 CM
• Stihl MS 461 / MS 661 CM
• Stihl MS 150 T-CE / MS 193 T / MS 193 CE Carving / MS 210 CM
• Stihl MS 461 R

In our service center you can sharpen your old chain or buy a new one.

Sharpening cost: 200 rubles!

Attention! Before contacting the service center!

In order to save your time, we ask you to find out the exact model of the chainsaw in advance.

Still have questions? Do you want to know the price of repairing a Shtil chainsaw? Call!

We try to provide the highest quality of service, so we have created a Quality Control Service especially for you.

Specifications

The Shtil 250 chainsaw is supplied as standard to the Russian market with two tires of different lengths: 4 and 16 inches. Depending on the task at hand, you can choose any one, with luxury versions such as Shtil MS 250

When choosing a chainsaw, you should not focus too much on the length of the bar; if necessary, the bar and chain can be replaced with a longer one, or vice versa, after purchase.

The main technical characteristics of the standard and improved models of the 250th saw are the same. Power 3.1 l. s., which translates into 2.3 kW. This is already 0.8 more than the household model Shtil 180. The working volume is 45.4 cubes. RPM 11 – 13 thousand. The chain has a pitch of 0.325 inches and a 1.3 link width.

The chainsaw weighs 4.6 kilograms. The volumes of the oil and fuel tanks are 0.2 and 0.47 liters, respectively.

Of course, it’s difficult to determine from the characteristics how a chainsaw will behave in practice; to do this, you need to try it at work and compare it with something.

Chainsaw piston group

The dimensions of the cylinder-piston group are determined primarily by the diameter of the piston, made of heat-resistant aluminum alloy. Regardless of the model, the chainsaw CPG consists of a cylinder, a piston, a holding pin and two clamps.

Chainsaw cylinder mirror

In order to increase compression in the working unit and, as a result, increase power, many manufacturers install two piston rings. The chainsaw's compression rings, made of special cast iron, fit tightly to the cylinder, resulting in the tightness of the combustion chamber.

Pro Shtil 250

The Shtil 250 saw is perfectly balanced and combines such qualities as high power and at the same time low weight and ease of use. The power allows you to install larger tires on this model, which means sawing thicker tree trunks, which increases productivity. Weight affects comfort when working with a tool for a long time. Small dimensions allow the saw to work in places with limited space or in dense thickets. This saw is convenient for clearing branches from a fallen tree or cutting out small growth.

If necessary, Shtil 250 can cope with more complex tasks, but you should not work with maximum loads for a long time. The resource of this model is still not the same as that of professional saws.

The Shtil 250 saw is designed using the most modern developments of German engineers, which we will talk about a little later.

Of course, the power unit of the Stihl MS 250 chainsaw cannot compare in power with the engine of a professional model, but it is also capable of a lot. The difference with a household chainsaw is felt as soon as you start making the first cut. If desired, buyers can purchase a richer package for the Shtil 250, in which it is additionally equipped with devices that increase the comfort of using the saw.

How to start a Shtil chainsaw - the correct procedure

To ensure that your Stihl chainsaw lasts as long as possible, you need to start it correctly. The level of load that affects the motor and other mechanisms of the tool when they are directly turned on depends on this.

To start a chain saw with a cold engine, you need to adhere to the following algorithm:

1. First of all, the operator must engage the chain brake by pushing its lever forward;
2. Next, you need to press the decompression valve several times - this will fill the engine cylinder with fuel and make it easier to start the internal combustion engine;
3. After this, you will need to press the fuel pump;
4. The operator must then move the throttle position lever to its lowest position;
5. Then you need to quickly pull the starter rope several times until the engine starts and stalls;
6. After this, the throttle position adjustment lever must be quickly moved up one position;
7. Next, you will need to quickly pull the starter cable towards you again. As a result, the chainsaw engine should start;
8. In the next step, the operator must fully press the throttle lever and hold it in this position. At the same time, you need to move the throttle position lever directly to the uppermost position with your second finger.

At the end, you need to slowly raise the chainsaw and turn off the inertia brake by pulling its lever towards you. As soon as the operator hears a characteristic short-term click, you can begin operating the chainsaw.

Features Shtil 250 and 250 C-BE

To improve the performance of the Shtil 250, the designers installed several modern developments on the chainsaw, which best affect the comfort and quality of the chainsaw. The first thing we will talk about is the compensator.

Compensator

A special device installed in the carburetor cover and connected to the air filter housing by a separate small channel. The essence of the compensator is that it allows air to enter the carburetor in addition to the fuel filter. This is necessary in those moments when the air filter is extremely dirty and does not allow the amount of air required by the engine to pass through.

On chainsaws that are not equipped with a compensator, a dirty fuel filter can cause an increase in fuel consumption and an over-richness of the fuel mixture. As a result, everything can end with carbon deposits under the piston rings and scuffing of the CPG. Accordingly, the saw will require expensive repairs, and the compensator can protect against all this.

You cannot operate a chainsaw for a long time with a dirty filter, even if it has a compensator. We recommend cleaning the air filter after every working day.

Carburetor heating

This function is most useful in winter, as it prevents carburetor icing. The operator can turn the option on and off as needed. To change the mode, you need to move the valve, which redirects warm air flows to the carburetor or vice versa.

In the summer, you need to make sure that the damper is open, because otherwise the engine will cool worse and it can overheat.

Chain brake

One of the safety mechanisms when working with a chainsaw is a manual inertial chain brake. If for some reason the chainsaw bar makes a sharp rebound, the brake will engage and the chain will instantly stop spinning, thereby reducing the risk of serious injury. For the chain brake to operate correctly, the operator must comply with several conditions:

1. Hold your hands as instructed, i.e. left hand on the front handle, right hand on the back handle.
2. Clean the mechanism in a timely manner, since it is located in the side cover, which receives a huge amount of sawdust.

Vibration reduction system

The chainsaw engine vibrates strongly during operation. Vibration can cause discomfort and reduce operator work time due to fatigue. To solve the problem, German engineers equipped the Shtil 250 with an anti-vibration system consisting of effective shock absorbers. Thus, Shtil 250 can be used for work even by those who have chronic diseases of the hands.

Combined control

Another system that adds convenience and is designed to facilitate the operation of the Shtil 250 is a combined control lever. Thanks to which, turning the ignition on and off is done with the thumb of the left hand. The suction mode is also activated in the same way. You never need to look for the switch; it is always at hand, which is especially convenient in case of an emergency.

Ematic

This is an officially patented system by Stihl, which is designed to reduce friction and increase the service life of the saw set. The system includes not only the part that is installed on the chainsaw, this is the oil pump and transport lines, but also the bar and chain of the chainsaw.

Classic chainsaw layout

Almost all professional and amateur chainsaws are equipped with two-stroke air-cooled gasoline engines.

Husqvarna chainsaw: main components

This assumes the presence of at least one cylinder with heat sink fins. The fuel supply system (carburetor) performs the function of a gasoline-air mixer. Dirt, dust, and shavings should not enter the working combustion chamber along with the fuel mixture, and filters are installed on the saws to clean the supplied air. Manufacturers recommend changing the filter once per season. In the interval between replacements, it must be cleaned once every 10-15 refills.

For convenience and ease of starting the internal combustion engine, any chainsaw is equipped with a starter, which is a reel with a wound cable and a handle. Even the most powerful Husqvarna chainsaw is equipped with a sophisticated starting mechanism.

In order to reduce the vibration transmitted to the feller's hands, a special device is installed on the tool. In addition, this mechanism prevents the tire from “driving” while cutting wood.

Chainsaw carburetor design

A carburetor is a device in which fuel is mixed with air and this mixture is supplied to the cylinder for combustion. When burned, the crankshaft is activated, to which the drive sprocket is connected to drive the saw set - the chain

The absence or malfunction of the mechanism in question will lead to the instrument being inoperable, so it is important that the device is in good working order and adjusted

The design of a chainsaw carburetor consists of the following components:

• Solid cast aluminum alloy body. The use of aluminum for the manufacture of this mechanism helps to lighten the weight of the tool
• Air supply diffuser located on the inlet side of the mechanism
• Jets are valves that serve to regulate the flow of the mixture.
• Atomizer - a device from which the fuel mixture enters the combustion chamber of the cylinder
• Float chamber - a device for creating and maintaining a certain level of fuel

A detailed design diagram of the device in question is shown in the photo below.

Chainsaw carburetor design

Setting up a chainsaw carburetor is an important step that every sawyer has to deal with. A chainsaw needs adjustment not only after purchase, but also in the following cases:

• Before running in the tool. How to set up the mechanism for proper running-in of a chainsaw is described in detail here
• After finishing the running-in process
• After engine overhaul
• During the operation of the tool, when malfunctions occur during operation and starting the motor

At the heart of the mechanism there are 3 screws for adjustment (on some Chinese models there are 2 screws), which serve as a control panel for the user. It is with the help of these screws that the chainsaw carburetor is adjusted independently and quickly. You can adjust an important component of the tool even in the field, without the help of specialists.

Why does the Shtil 250 chainsaw not start?

Sometimes there are situations when the saw may not start. As a rule, more than 50% of saws that did not start and were taken to a service center did not start due to a violation of the cold start algorithm.

The saw starting algorithm and the reason why the Shtil 250 may not start

The operating instructions describe in detail the process of starting the saw, according to which you first need to press the primer several times, then lower the control lever to the lowest position.

After this, pull the trigger several times until the saw grabs (it starts and stalls for a split second, this phenomenon is also called a flash). Next, you need to move the control lever up one position and start the saw, then press the gas once to set the idle speed.

To prevent the saw from starting, it is enough to violate only one point, namely, not to move the lever one position up after the flash has passed. Thus, the saw will not have enough air and fuel will flood the spark plug. To start the saw after the spark plug has been filled, it is necessary to bleed the engine. How this is done is described in detail in the operating instructions.

Technical characteristics of the Stihl MS 250 chainsaw

The Stihl chain saw in the 250th factory configuration features improved factory parameters that allow the model to cope with the most complex household and construction tasks.

Key features of garden tools include:

• ICE power – 2.3 kW/3.1 l. With.;
• chain rotation speed at idle/maximum speed – 2,800/10,000 rpm;
• fuel tank – 470 ml;
• recommended tire length – 35–40 cm;
• chain pitch – 3/8 “;
• weight including saw set – 4.7 kg.

When developing the Stihl MS 250 chainsaw, the manufacturer managed to achieve a low noise level when the engine is running. When operating under maximum loads, this parameter of the garden tool is 105 dB.

Description

The Shtil 361-ms chainsaw is a professional, powerful chainsaw with a long service life, designed for long-term use in both normal and difficult conditions. It has dynamic acceleration function, high torque. Considering the size of the chainsaw, the vibration level of the device can be called low. The chainsaw is equipped with a decompression valve and the ElastoStart system.

Chainsaw Stihl 361-MS

Purpose of the Shtil 361-ms chainsaw: professional construction work with wood, creation of wooden structures for any purpose, trimming branches and branches, preparation of wooden beams, boards, logging production, use for municipal purposes, for example, in forestry areas, sawmills.

The engine power of the Shtil 361-ms chainsaw is 3400 W (4.6 hp). The engine cylinder capacity is 59 cubic meters. cm. Two varieties of the same model are available - with a tire length of 40 cm and 45 cm.

How the Shtil 361-ms chainsaw works - video:

The choice between the 250th and 260th Shtil model

Readers have many questions about the choice between Shtil 250 and 260 chainsaws.

The answer can be unequivocal. The Shtil 260 saw is better for the reason that it is a saw for professional use and, during production, completely different requirements were placed on it than the Shtil 250, intended for agriculture.

Accordingly, the cost of these models has a significant difference. Shtil 260 is sold at almost 50% more expensive than Shtil 250. Of course, for those who don’t mind paying for a professional tool and using it in private households, it’s definitely better to buy Shtil 260, but the 250 also lasts for many years and practically does not kill if done in a timely manner. THAT and normal attitude.

How to properly prepare a Shtil chainsaw for work

1. Initially, the chainsaw is assembled.
2. The fuel mixture is prepared in the correct ratio of gasoline and oil (50/1).
3. The saw is refueled with freshly prepared fuel.
4. Oil for the stihl chainsaw chain is poured into the appropriate tank.
5. A chain is installed on the chainsaw.
6. The chain saw is started.
7. The operator adjusts the “Calm” chainsaw at idle speed.
8. The amount of oil supplied to the chain is checked.

New equipment owners are often concerned about the following questions:

1. What kind of gasoline is used for the Shtil chainsaw, and how to dilute it?
2. How to tension a chain on a Stihl chainsaw?
3. What is the gasoline consumption rate?
4. How to start a Calm chainsaw correctly?

We answer: all Stihl chainsaws run on high-quality unleaded gasoline with an octane rating of at least 92. Gasoline is diluted with high-quality motor oil for two-stroke power plants of the Stihl brand. The ratio of gasoline to oil is 1/50 (0.1 liters of motor oil and 5 liters of fuel).

We invite you to watch several videos that show how the saw starts, how the chain is put on it and much more:

Running in the Shtilev chain saw

The saw is already ready for use from the factory; the owner of the equipment needs to operate it in a gentle mode for some time - the power should not exceed 50%. The duration of this period is measured in the amount of fuel consumed in the tank; professionals advise running-in during the combustion of 4-8 full tanks of the fuel mixture.

Stihl chainsaw maintenance

Maintenance of a chainsaw can be carried out in several stages:

Daily maintenance of the chainsaw:

• checking the condition before operation;
• cleaning tools after work.

Scheduled inspections:

• carburetor adjustment;
• chain sharpening;
• carrying out minor repairs.

Service maintenance - troubleshooting.

To sharpen the chains of Shtil chainsaws, a special device or machine is used (shown in the photo below):

Problems with Shtilevsky gasoline chain saws

We list the most common malfunctions that owners of gasoline saws have to deal with:

Stihl chainsaw won't start:

• ran out of fuel;
• the ignition system has failed;
• the air filter is not cleaned;
• fuel is not supplied;
• carburetor is dirty.

The “Calm” chainsaw starts and stalls, reason:

• the filter is clogged;
• ignition fails.

The chainsaw does not gain speed:

• the carburetor needs to be cleaned, adjusted or replaced;
• filters are clogged and require cleaning.

You will find a more complete list of malfunctions indicating the causes and ways to correct problems in the repair manual included in the instructions.

We invite you to watch a video on how to repair and adjust chain lubrication:

Engine malfunctions

• The engine will not start;
• starts but stalls;
• works unsteadily;
• does not develop power, i.e. It runs fine at idle, but stalls under load.

When repairing a chainsaw at home, you need to use the method of elimination. Our client is left to check one by one the possible causes of the malfunction, starting with the development of those, the verification and elimination of which takes less time (see here about the device and operation of a two-stroke engine).

Ignition system

. Almost all types of engine problems listed above can be caused by ignition system failures. Therefore, when they occur, it makes sense to start troubleshooting with a spark plug. This is all the more justified since the state of the latter can provide useful information about the operation of the fuel system. So, if a problem occurs, you need to unscrew the spark plug and inspect it.

The wire is disconnected and the spark plug is unscrewed with a special wrench.

If the spark plug is dry, this means that the problem is most likely not in the ignition system, but in the fuel mixture not entering the cylinder. You can wrap the spark plug back and get to work on the fuel system. If the spark plug is heavily splashed with fuel mixture, it means there is an excess of it. This may occur due to carburetor misadjustment or violation of starting rules. The spark plug is wiped and dried, the cylinder is dried by turning off the fuel supply and operating the starter. to ventilate the combustion chamber and remove excess fuel. Then install the spark plug in place and repeat the start.

The presence of a large amount of black carbon also indicates a malfunction in the fuel system.

The ratio between oil and gasoline in the mixture may be incorrect, the carburetor may not be adjusted, or low-quality oil may be used. The spark plug is washed in gasoline, cleaned of carbon deposits with a needle or awl, the electrodes are cleaned with fine sandpaper and replaced.

In all these cases, it would be a good idea to check the gap between the spark plug electrodes. Depending on its brand, it should be in the range of 0.5-0.65 mm. You also need to check the spark plug seal. All about repairing a chainsaw with my own, oil is leaking from a champion saw. If it is worn out or damaged, the tightness of the combustion chamber may not be ensured, which leads to a decrease in compression in the cylinder and problems in engine operation.

Even if, when checking the spark plug, there is good reason to believe that the fault is in the fuel system, you need to check the spark plug for the presence of a spark. At least to be sure that everything is in order. For this:

• put the ignition cable on the spark plug;
• using pliers with insulated handles, apply the thread or nut of the spark plug to the cylinder;
• pull the starter handle and watch. whether there is a spark or not.

Read:

If there is no spark, you just need to replace the spark plug. If the new spark plug does not have a spark, you need to check the condition of the high-voltage wire for a break and contact with the spark plug.

The reason for the lack of a spark may also be a faulty ignition module or a violation of the gap between it and the flywheel magnetic circuit. It should be 0.2 mm. Violation of the gap becomes especially likely if the saw was previously disassembled and the flywheel and ignition module were removed. The gap is set using a 0.2 mm thick gasket placed between the flywheel boss and the ignition module. A faulty ignition module must be replaced.

Having checked the ignition system in this way and not finding a malfunction, you can move on to the fuel mixture supply system.

Fuel supply system

. If by inspection of the spark plug it is determined that fuel is not entering the cylinder, all possible reasons for this need to be considered. It could be:

• failure of fuel to flow from the tank due to a clogged hole in its lid (breather), while a vacuum is created in the tank, preventing fuel from leaking out;
• contamination of the fuel filter installed in the tank;
• no or insufficient supply of fuel mixture
  from the carburetor to the cylinder.

To diagnose the first two reasons, it is enough to disconnect the fuel hose from the carburetor and see whether fuel flows out of it or not. If it flows in full stream, the breather and filter do not need to be checked; if it does not flow or flows weakly, we can assume that the cause of the malfunction has been found. The breather is cleaned with a needle. The fuel filter is removed through the filler hole of the empty fuel tank using a wire hook, along with a suction hose, from which the filter is disconnected and cleaned or replaced with a new one. Chainsaw manufacturers recommend changing the fuel filter every three months.

Basic faults and DIY repairs

Like all gasoline units, the Shtil 250 chainsaw has basic malfunctions that most often occur with it. Let's figure out what these problems are and how to fix them yourself.

Starter cord and spring faults

One of the most common breakdowns on any chainsaw is a broken starter cord or a broken return spring. Repairing these faults is quite simple. To do this, you need to remove the starter from the chainsaw (unscrew the four mounting screws). Next, using pliers, remove the stopper from the central shaft of the starter (in some versions, the mechanism is fixed with a screw), and then remove the washer and trigger pawl.

To replace the chainsaw cord, a reel is removed from the central shaft, onto which the cord is wound and the torn element is removed from the mount. A strong knot is made on the new cord, after which the cord from the end opposite to the knot is threaded into the mounting hole on the reel and pulled through it.

Next, the reel, followed by the pawl and stopper, are installed in their places, after which the lace is wound around the reel in a clockwise circular motion. The end of the cord is threaded through the starter body and a handle is installed on it, after which it is slightly stretched and secured with a knot. Thus, it turns out that the starter coil is under slight tension all the time, due to which the handle does not dangle, but is held in its seat.

If it is necessary to change a burst spring, it is convenient to do this after the cord reel has been removed. The new spring is installed with the body facing up. Next, the starter is assembled according to the algorithm described above.

Before installing the spring, it must be lubricated. Regular motor oil is suitable for lubrication.

Below is a video about repairing a starter on a Shtil chainsaw. The video is in German, but the procedure is shown in as much detail as possible and, if necessary, it can be repeated even by those who have never dealt with repairing a chainsaw.

Replacing oil seals

Oil seals are a rubber element with a spring that is installed on the motor shaft and protects against air penetration.

As soon as the seals become unusable (over time, this happens on all chainsaw engines, since the seals are made of oil-resistant rubber and lose elasticity over time), they must be replaced, since air leaks into the engine crankcase.

To replace the seals on the Shtil 250 yourself, you will need a special tool with which you can completely disassemble the chainsaw, as well as knowledge of all the nuances of disassembly and assembly.

Advice: if you do not have experience in repairing gasoline saws, it is better to turn to professionals.

Troubleshooting algorithm

In all other cases, the search for ignition problems begins from the end and in order. After each step, check the spark.

1. Replace the old spark plug with a guaranteed working one.
2. If the model has a removable spark plug cap, remove it, and the exposed spark plug wire is connected to ground with a gap similar to that of a spark plug. They pull the starter. If there is a spark, the problem is in the cap. She is being eliminated.
3. Change the spark plug wire where it is possible to remove it from the source.
4. Visually inspect the wires from the switch. Vibration or contact with metal can cause damage. If there are friction points, the wire is replaced, even if there is no external damage to the insulation. You can use a tester or multimeter to check the wire.

Read also: What is the measurement accuracy of a device

This is where minor and easily fixable problems end. If the problem is not solved, then the reason is more serious. Modern coils and ignition systems on most chainsaws are very reliable. They are designed to last even longer than the entire chainsaw as a whole. There are no mechanical moving parts like older cam systems. They are sufficiently insulated from clogging and moisture.

If, due to an accidental manufacturing defect, an interturn short circuit occurs in the coil or the electronics fail, these parts cannot be repaired. Will need to be replaced with new ones.

It is not uncommon for a mechanical failure to occur. Due to wear or destruction of the crankshaft bearing, play appears on it. And then the magnetic rotor begins to touch the body of the ignition system, inside which it rotates. This is a serious breakdown. You will need to “halve” (disassemble) the entire engine, replace the bearing, and put everything back in place.