How to Put a Piston On a Chainsaw Correctly

When working with a chainsaw, in some cases you can see how, when cutting a tree trunk with a diameter of more than 30 cm, the tire gradually starts to sideways. This is especially noticeable when it is necessary to cut large-diameter trunks using the double-cut technique, that is, they are first sawed from above, and then turned over and sawed to the end.

How to Put a Piston On a Chainsaw Correctly

Chocks, crooked sawed off by a chainsaw, have an uneven surface, this gives some discomfort when they split into logs. And the use of such a chainsaw when laying a log house, for example, for cutting the bars, is not at all permissible, since the ends will be uneven.

Why the chainsaw leads away

Discomfort at work, decreased productivity, increased fuel consumption, cut curve, these are all the negative consequences of this phenomenon, but what is the reason?

There are actually only three reasons:

  1. Uneven grinding of teeth;
  2. Using a circuit that does not match the bus parameters or vice versa;
  3. Increased wear of the chainsaw headset.

Uneven sharpening

According to the instructions for sharpening chains, it is necessary to grind the teeth at the same distance, and independently, on which side they are located. By observing this simple requirement, you can protect yourself from the problems associated with the fact that the chainsaw takes away when sawing.

Unevenly chipped teeth are the most common crooked cut problem.

Sharpening the chain with a file, it is not always possible to control the length of the tooth using the technique of counting the number of movements with a file.

This is due to the fact that the wear of the teeth is uneven, some are damaged more and more file movements are required in order to bring them back to normal, which means that the size of such teeth will decrease significantly compared to the others.

How to avoid incorrect sharpening

In order to prevent the cut curve due to uneven sharpening, you can use a special grinding machine to straighten the chain from time to time or with severe damage. Buy a machine and sharpen it yourself or give it to the workshop for sharpening.

The fact is that the machine during grinding is adjusted according to the most worn tooth, which has a smaller size among all. After the sharpening is carried out, all the teeth will have the same size, which will be equal to the tooth that was adjusted.

The disadvantage of this method is that the resource of the chain is significantly reduced, because even the undamaged teeth have to grind very much. Try to use the chainsaw more carefully, keep an eye on nails and any other metal products that might come across when cutting old boards and other rubbish.

Using the wrong chain

It’s not a secret that the chainsaw tire, like the chain, has several basic characteristics, one of them is the width of the groove for installing the chain. The width of the groove may have several basic dimensions:

Imagine that we take a chain with a seating width of 1.1 and install it on a tire with a groove of 1.3 mm. Initially, by pulling it well, we may not notice the difference, but as soon as the stretch loosens a little, a gap of 0.2 mm will not allow it to evenly move along the tire, it will bend to one side and we will again get a crookedly sawn material.

When buying a spare chain for a chainsaw, name its exact dimensions, not the make and model of the chainsaw. For the same model of chainsaws, different tires can be installed and, accordingly, the chains will also be different.

Check the width of the chain, you can use the caliper.

To eliminate the malfunction, if the tire of the chainsaw has not yet been severely damaged and there is no uneven wear on it, only the chain will need to be replaced. If wear is already observed on it, a completely new kit must be installed.

Increased wear

If the chainsaw is sawing crookedly in an arc, the cause may be the excessive wear of the saw set. You can check by conducting a visual inspection of their contacting surfaces. To do this, the tire must be removed from the chainsaw and look at its plane of contact with the chain from the end, positioning it at eye level so that the landing groove under the chain is fully visible.

With this inspection, you can visually assess the wear of the left and right side of the tire with respect to the groove. As a rule, the wear of the edges should take place evenly, and in the event that one side is sharpened more, to eliminate the malfunction, it is necessary to replace the defective one with a new one.

For uniform tire wear, some manufacturers recommend turning it over periodically. But it is worth remembering that not for all headset models, this recommendation is correct, since many manufacturers indicate the direction of movement of the chain along the tire surface, and accordingly such a part can be installed in only one position.

The figure below shows several types, the upper one has the direction of installation of the circuit, as indicated by the icon on the tip of the bus and a direction indicator.

Experienced masters of service chains for repairing chainsaws, if excessive wear is detected, advise a complete diagnosis of the lubrication system of the saw headset, since with a correctly functioning lubrication system and installing a chain to the corresponding chain of the chainsaw, this phenomenon should not be observed, therefore, the oil supply system may have malfunctions or improper adjustment.

If you observe a crooked cut while working with a chainsaw, the first thing you should pay attention to is the correspondence of the chainsaw chain to its tire. If everything is normal, check the sharpening of the teeth and the wear of the tire, in case of increased wear, check the operation of the lubrication system, because the problem may be in it. And the main thing to remember is that everything is interconnected in a chainsaw and the use of low-quality oils for chain lubrication can cause premature wear and loss of performance of the chainsaw.

DIY chainsaw repair

All malfunctions of chainsaws can be divided into two main groups: problems of the engine with all its components and systems (ignition, fuel supply system, cylinder-piston group, exhaust system) and malfunctions of other components (chain brake, lubrication system, clutch, the tire etc.).

Engine malfunctions

  • the engine will not start;
  • Starts up, but stalls;
  • it is unstable;
  • does not develop power, i.e. normally works at idle, but stalls under load.

When repairing a chainsaw with your own hands, it is necessary to act as an exception — to inspect alternately all the possible causes of the malfunction, starting with those that take the least time to check and eliminate (see here for the design and operation of a two-stroke motor).

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

The wire is disconnected, and the candle is twisted with a special key.

If the candle is dry, it 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 candle back and take up the fuel system. If the candle is heavily sprayed with the fuel mixture, then there is an excess of it. This may occur due to misregistration of the carburetor or violation of the rules for starting. The candle is wiped and dried, the cylinder is drained, cutting off the fuel supply and working as a starter to ventilate the combustion chamber and remove excess fuel. Then set the candle in place and repeat the launch.

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

The ratio between oil and gasoline in the mixture may be violated, the carburetor is not adjusted, or poor-quality oil is used. The candle is washed in gasoline, cleaned with a needle or an awl of carbon deposits, clean the electrodes with a fine sandpaper and put in place.

In all these cases, it is not superfluous to check the gap between the electrodes of the candle. Depending on its brand, it should be in the range of 0.5-0.65 mm. It is necessary to check the sealing gasket of the candle. If it is worn 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 the engine.

Even if in the case of 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 a spark. At least in order to be sure that everything is in order with this. For this:

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

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

A chainsaw is a simple device that, with proper care, can last a long time. At the same time, the saw is a tool subject to various loads and, therefore, breakdowns still occur. You will learn about what caused the specific malfunction and how to fix it from this article.

Видео: How to Put a Piston On a Chainsaw Correctly

Structural components of chainsaws

All chainsaws are similar in structure, regardless of whether they are European-made (ECHO, Stihl, Husqvarna) or domestic (Cedar, Ural). The main elements are located inside the case. a fuel tank and an engine, and outside the starter, handle, saw part (tire) with a chain. A sharp jerk of the cable starts the engine, and that. the saw blade.

To get started, we suggest you familiarize yourself with the video clips that show how the chainsaw is arranged and how it works:

From time to time, malfunctions occur in the saw, which requires disassembly. What can happen with such a simple mechanism as a chainsaw? At least the following:

  • Ceases to start;
  • Starts up, but soon stops;
  • It ceases to function in the cut;
  • Loses its power;

Most of the problems are associated with interruptions in the engine (fuel supply system, exhaust system, ignition, cylinder-piston part), or with malfunctions of other systems and components (clutch, chain brake, tire, lubrication system). Consider the most common breakdowns and methods for eliminating them.

A working chainsaw starts up with one jerk and does not fail to cut

Essential skills and repair tools

Most of the malfunctions of chain gasoline saws can be eliminated with your own hands. True, this requires an understanding of the device of the chainsaw and how the nodes function among themselves. As for the tool, it is most often necessary:

  • screwdrivers (slotted and power);
  • combination wrench included in the kit or conventional wrenches with heads of various sizes.

Chainsaw tire repair

Chainsaw tire repair. An asterisk stuck on the chainsaw tire and it would seem that nothing remains as it throws it away.

Repair it yourself or give it to a service center

It should be understood that not every problem can be solved independently. Not every owner of a chainsaw has a compressometer or a special device at home that allows you to create a vacuum and the right pressure, for example, to check the crankcase for leaks. In this case, you just can’t do without turning to specialized specialists.


In most cases, the engine encounters the following problems:

  • the engine stopped starting;
  • the engine starts, but stalls after a while;
  • the engine is not able to develop the necessary power;
  • the engine is extremely unstable.

How to check crankshaft oil seals

The presence of leakage of oil seals can be checked only by reaching the crankshaft, and carefully examining it for leaks. On how to do this correctly, you can find on the video:

How to check compression on a chainsaw

At a compression level below 8 atmospheres, the engine will not have enough power, which means that the chainsaw will not be able to fully function.

To measure compression, you must:

  1. Remove the protective cover and unscrew the spark plug.
  2. Insert the tip of the compressor into the hole where the candle should be.
  3. Using the starter cord, rotate the piston and remember the maximum reading of the measuring device.

How to put the piston on a chainsaw

Work on replacing the piston for most models of modern chainsaws is carried out according to the following algorithm:

  1. The top and side covers are removed.
  2. The candle is twisted.
  3. They are removed from the shock absorbers of the stopper and the handle is disconnected from the housing.
  4. The leading asterisk and starter acts in film.
  5. A piston stop is installed in the spark plug hole and the nut is fixed to fix the flywheel and the clutch.
  6. The flywheel, clutch, worm gear of the oil pump located immediately behind the clutch mechanism are removed.
  7. The screws securing the carburetor and air filter are untwisted, after which these components are removed together with the engine control lever.
  8. The ignition coil is removed, as well as the muffler.
  9. The saw is turned upside down and, having unscrewed the screws that secure it to the body, the engine is disconnected.
  10. The pan unwinds and the piston is removed.
  11. Since the piston is removed only together with the crankshaft, it is necessary to remove the snap rings to detach it.
  12. The old piston changes to a new one, but as carefully as possible. This is caused by the high fragility of the compression rings.
  13. The sump is put in place, and instead of the gasket, a sealant is used.

All subsequent actions are carried out according to the reverse of the disassembly algorithm.

Troubleshooting algorithm

If you are sure that you can assemble the chainsaw after disassembly, then a screwdriver is in your hands. To establish the true cause of the malfunction, it is necessary to analyze the condition and behavior of the saw.

Fuel system repair

Fuel may not enter the cylinder for the following reasons:

  • Fuel filter contamination. Remove the fuel hose and check for fuel leaks. If the jet is weak, you may need to clean the filter. It is taken out through the filler hole of the fuel tank and cleaned, in case of severe contamination it is replaced with a new one. As a preventive measure, it is recommended to replace the fuel filter every three months.
  • Clogged breather (holes in the fuel cap). Also check by disconnecting the hose, in case of blockage, clean with a needle.
  • Lack or insufficient amount of fuel. There may be several reasons for the malfunction. The first reason is clogged air filter. The air ceases to flow into the carburetor in the right amount, in this regard, due to too rich fuel mixture, the engine is disrupted. The contaminated filter is carefully removed, cleaned and washed in water, then dried and replaced.

Another reason is the incorrect carb adjustment. Adjustment is made by three screws.

Timely replacement of the fuel filter ensures full fuel supply

The fuel hose and choke drive must fit snugly against the fittings.

The throttle control lever cable must be in place

During operation, you must use the instructions, otherwise you can only make it worse.

Related article: Adjusting the carburetor chainsaw: technical nuances

And the last reason is a violation of the integrity of the membrane or clogging of the carburetor channels.

To repair the carburetor yourself, you need to get acquainted with all its details

All parts must be clean, dry and intact.

Replacing Wear Parts

If you do not replace the wearing parts in time, their excessive wear will adversely affect the other parts of the chainsaw. In particular, if you do not change the tire and the drive sprocket in time, increased vibration will adversely affect the crankshaft bearings. The maximum depth of the tooth teeth should be 0.5 mm. In practice, sprockets are often operated up to a wear depth of 1 mm or more, without suspecting that this leads to an increased load on the crankshaft bearings and their accelerated failure. When 3-4 chains are worn, it is necessary to change the tire itself, by this time its wear reaches its limit values.

Tire chainsaws wear out especially hard in the area that is cut most often, usually the underside of the guide bar. For uniform wear, each time the chain is replaced, the tire must be turned 180 ° relative to the horizontal axis.

When installing a new chain, a new drive sprocket should be installed. Since under normal load the service life of the drive sprocket is twice as long as the service life of the chain, it is advisable to use one sprocket for alternating operation of two chains. Thanks to this, the sprocket and chains wear out almost simultaneously. If a new chain is placed on a worn sprocket, then the leading chain links wear out much faster. For cost-effective operation of the chainsaw, always spend together: one guide bar, two chain sprockets, four saw chains.


A “rich” or “poor” fuel mixture will sooner or later cause a breakdown. Perhaps even expensive. To prevent this from happening, it will be useful to regularly check the filter for abrasions, as well as for a breakthrough of the filter cloth itself.

How to check the fuel filter and replace

To check the current state of the fuel filter, the following steps must be taken:

  1. Remove the fuel hose from the carburetor fitting and direct it into the working container.
  2. Click on the so-called “swap” several times.

If gasoline arrives unevenly and jerkily, then it’s time to put a new filter element. This is done quite simply:

  1. The fuel tank cap is unscrewed.
  2. Using tweezers or any other device, the filter itself is removed.
  3. Having disconnected the old filter, it is necessary to put a new one and lower it into the fuel tank.

How to clean the air filter

If enough air is not received, the fuel mixture becomes too enriched, which leads to a disruption in the normal operation of the engine. Regular purging of the air filter, and in especially neglected cases, washing in soapy water will prevent such problems.

Please note that rinsing in acetone, gasoline or other aggressive solutions is not allowed. This can lead to a violation of the integrity of the filter element.

Uncertain Category Failure

In some cases, owners of chainsaws have to solve more complex problems to fully restore the functionality of their cutting tool.

Chainsaw does not develop full power

In addition to the problems discussed above with a lack of gas or air entering the cylinder, the reason for the low power may be a clogged muffler.

If you do not periodically clean the muffler clogged with combustion products, then the problem of poor engine power may not be the only one.

Carburetor depressurization and nozzle blockage

Over time, the screws securing the carburetor cover may loosen or the gaskets become unusable. A clogged filter or an unqualified replacement may result in clogged nozzles. All this also negatively affects the operation of the chainsaw and shortens the life of the tool.

To prevent this, it is enough to periodically inspect the saw and, if necessary, evenly tighten the screws.

Chainsaw does not hold idle

It often happens when, after prolonged transportation and constant use, the chainsaw refuses to idle smoothly. This problem is usually resolved by adjusting the carburetor.

You can learn how to properly debug a carburetor from this video:

If the carburetor is set up like a clock, then you need to check:

  1. Fuel system. To start more logically with the fuel pump.
  2. Muffler. It is very likely that due to the abundance of soot accumulated, the engine cannot function normally.

Chainsaw loses power under load

If the saw power is lost somewhere during operation, then the problem should be sought in the following places:

  1. In the silencer. He, as you already understood, has the property of clogging.
  2. In a clogged fuel filter.
  3. In a poorly functioning fuel pump.

Failure of other systems

In some cases, users of chainsaws note other problems that do not significantly affect the operation of the tool.

Why is a chainsaw smoking

Most often, excess smoke appears when the oil is excessively added to the fuel mixture, which does not have time to completely burn out. You should also check if the carburetor settings have gone wrong.

Recoil when starting a chainsaw

For the most part, recoil at the time of starting signals the clamp of the decompressor. If the tool is not equipped with a decompressor, then most likely the ignition system has lost.

Failures of the Chinese chainsaw: a review of the popular and ways to solve them

The most popular faults in Chinese chainsaws include:

  1. Poor lubrication system. Clogged oil channels are cleaned, and if the oil pump fails, a replacement is necessary.
  2. The starter cable breaks.
  3. Damage to the plastic axis of the starter. To replace it, an ordinary metal bolt is suitable.

In the case of the slightest suspicion of incorrect operation of the chainsaw, it is worth immediately to make a complete diagnosis of the tool. Only with proper operation and timely maintenance can you count on the long term use of the chainsaw.