How to properly install the piston on a chainsaw

How to put the piston on a chainsaw correctly

One of the most important parts of any chainsaw is the cylinder-piston group (CPG), which transmits the rotational motion to the drive sprocket. Despite the reliability of this unit, most models require diagnostics and repair over time. It is the performance of the chainsaw’s CPG that determines the power of the unit, its ease of starting, the presence of idle and the consumption of the fuel mixture.

Causes of piston chainsaw malfunctions

There are many reasons for the failure of the CPG, which are usually divided into two main categories: natural wear and tear and artificial malfunctions. The first type of malfunction, as the name implies, is the physical wear of the rubbing parts of the piston group. The second category is more extensive and implies:

  • strong overheating of the internal combustion engine and, as a result, the appearance of thermal seizures on the surface of the piston;
  • breakage of the lower part of the piston (skirt) due to the duration of the chainsaw operation at maximum speed;
  • ingress of foreign particles into the combustion chamber and the occurrence of mechanical damage to the CPG;
  • breakage of the compression (piston) ring due to severe wear or exceeding the permissible saw speed;
  • discrepancy between the recommended portions of gasoline and oil when preparing the fuel mixture.

Experts do not recommend disassembling the CPG for no particular reason. However, if the tool has significantly lost power, there is a metallic ringing in the internal combustion engine, or the crankshaft does not turn when the starter jerks, the piston chainsaw should be diagnosed. First of all, to identify engine malfunctions, it is necessary to measure the compression in the cylinder. With a significant deviation from the values ​​recommended by the manufacturer, we can safely say that there are scratches, wear and tear on the surface of the cylinder or piston. It is the drop in compression that is the basis for the complete disassembly and repair of the piston group of the chainsaw.

For the prompt diagnosis of the CPG for a breakdown of the chainsaw compression ring or scuffing in the cylinder, professionals advise to remove the muffler and assess their condition through the outlet window.

On the video you can watch a detailed video instruction in which the master showed in all details how to properly disassemble the saw and install a new piston on it. Also in the video you can see how the saw is cleaned correctly during the repair process.

How to change a piston on a STIHL 180 chainsaw

If you need to replace the old piston and install a new one, you need to know how to do this correctly and follow a certain algorithm of actions. You also need a small slotted screwdriver, a special STIHL combination wrench, a power screwdriver, a hammer, a soft material drift, a compressor and a STIHL piston stopper.

When starting work on replacing the piston or piston group assembly, the chainsaw must be cleaned of dirt as efficiently as possible. Further, the work is carried out according to the following algorithm:

  • The top cover is removed from the saw and the spark plug is unscrewed.
  • Side cover is removed.
  • Using a power screwdriver, the stoppers are removed from the shock absorbers of the chainsaw, after which its handle is disconnected from the body.
  • Next, you need to remove the drive sprocket and starter.
  • Install the piston stopper in the spark plug hole and loosen the flywheel nut and clutch.
  • Remove the flywheel, clutch and oil pump worm drive mechanism, which is located behind the clutch.
  • Loosen the two screws securing the carburetor and air filter. Remove filter, engine control lever and STIHL carburetor.
  • Remove ignition coil and muffler.

After all these operations have been carried out, it is necessary to clean the saw from dirt again, then turn it upside down and unscrew the four screws securing the engine to the chainsaw body. By unscrewing the screws, the motor is separated from the housing and cleaned again.

On the removed engine, the pallet is untwisted and removed, after which the piston assembly with the crankshaft is removed from the engine.

When removing the piston from the cylinder, you must remember how it was located relative to the cylinder.

Next, using a small screwdriver, the piston pin retaining rings are removed, and the crankshaft is disconnected from the piston.

In the case when it is necessary to replace only the piston, you can install it on the crankshaft, then mount the piston pin circlips, while positioning them so that the snap ring break point is directed downward. This is necessary in order to prevent the circlip from spontaneously jumping out when the engine is running (according to the STIHL manufacturer’s instructions). After that, the compression rings are installed, the cylinder is lubricated with engine oil and the engine is assembled.

The work of installing the piston into the cylinder must be carried out with utmost care, since the compression rings are fragile and easily break.

The crankcase is installed on the engine, a sealant is used as a gasket, after which four fastening screws are mounted and tightened crosswise. Further, the engine is installed on the body of the chainsaw. Subsequent assembly is carried out according to the reverse disassembly algorithm.

Description of the piston group of the STIHL 180 chainsaw

On the STIHL 180 chainsaw, the piston group has a diameter of 38 mm. The dimension of the chainsaw CPG is determined by the piston diameter, the cylinder is slightly larger. As standard, the MS 180 CPG is supplied complete with a piston pin, two piston rings and two retaining rings.

The inner surface of the cylinder must be perfectly sanded and have a glossy sheen, which must be taken into account when purchasing a replacement cylinder head for a STIHL ms chainsaw. If there is damage to the inside of the cylinder, it is not necessary to install such a cylinder.

A distinctive feature of the CPG on the STIHL MC 180 is that it has two compression rings, while almost all of its main competitors have only one. According to the manufacturer, the installation of a pair of rings makes it possible to better stabilize the piston in operation, enhance its cooling and increase the compression in the engine, thereby improving starting.

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 CPG of the chainsaw consists of a cylinder, a piston, a retaining pin and two retainers.

When buying a piston chainsaw, you should pay attention to the inner surface of the cylinder, which must be polished and have a glossy shine. In the presence of damage, scratches, experts do not recommend installing such a cylinder.

In order to increase compression in the working unit and, as a result, increase power, many manufacturers install two piston rings each. Chainsaw compression rings made of special cast iron fit snugly against the cylinder, which ensures the tightness of the combustion chamber.

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Algorithm for replacing a piston chainsaw

If it is time to replace the CPG of the chainsaw, you need to know that for each specific model there is an individual algorithm of actions. To facilitate disassembly / assembly work, you must prepare a spark plug wrench, a large flat screwdriver, a hammer, a compressor for cleaning the unit parts, a set of open-end and socket wrenches. Regardless of the manufacturer and design features of the model, before removing the cylinder of the chainsaw, the following work must be performed:

  • Dismantling the upper protective cover;
  • Unscrewing the spark plug;
  • Removing the side cover;
  • With the help of a large flat screwdriver, the stoppers are removed from the shock absorbers;
  • In the channel of the candle we place a lace to fix the crankshaft and unscrew the clutch and flywheel nut;
  • Dismantling the drive chain sprocket;
  • We remove the carburetor with an air filter;
  • Removing the ignition module and exhaust system.

After removing it from the base of the power unit, unscrew the pallet and remove the crankshaft with the piston from the cylinder. Using plumbing tweezers or a screwdriver, we dismantle the piston pin stoppers.

Before dismantling the piston, it is necessary to remember its location in the cylinder, so that later you do not waste time on re-disassembling and assembling the power unit.

Chainsaw pan sealant

Before starting the assembly, it is necessary to clean the parts and assemblies of the unit from dirt, sawdust residues, dust with compressed air, rags and other means. The first step in replacing a piston chainsaw is to install a piston on the crankshaft. We fix it on the connecting rod with a steel pin included in the delivery set of the CPG. In order to prevent arbitrary falling out of the retaining rings, it is recommended to install them with a cut down. Next, we mount the compression rings on the piston, but due to their fragility and fragility, this operation must be approached as carefully as possible. To prevent the formation of scratches before installing the piston in the cylinder, the piston must be lubricated with oil. Before installing the crankcase (pallet), you will need to degrease its mounting surface and apply a layer of heat-resistant sealant. We assemble the chainsaw in the reverse of the algorithm described above.

Husqvarna 359 Chainsaw Piston and Cylinder Replacement

Often, replacing the chainsaw piston, crankshaft and compression rings solves problems with idle speed and problematic starting of the internal combustion engine.

Replacing a piston on a chainsaw is one of the most popular services in our workshop. This service is one of the most expensive because implies a major overhaul of the engine. The main reasons for the failure of the CPG, mainly, is the neglect of the rules for the storage and operation of the saw.

The main malfunctions of the STIHL ms 180 chainsaw are associated with the piston group. Consider the main reasons why the piston needs to be replaced. Let’s give a description of the piston and the algorithm for its replacement.

Replacement piston group of chainsaw 4500

The video describes a detailed replacement of the piston group of a chainsaw, How to do it correctly, in stages and without.

How to change a piston on a STIHL 180 chainsaw

If you need to replace the old piston and install a new one, you need to know how to do this correctly and follow a certain algorithm of actions. You also need a small slotted screwdriver, a special STIHL combination wrench, a power screwdriver, a hammer, a soft material drift, a compressor and a STIHL piston stopper.

When starting work on replacing the piston or piston group assembly, the chainsaw must be cleaned of dirt as efficiently as possible. Further, the work is carried out according to the following algorithm:

  • The top cover is removed from the saw and the spark plug is unscrewed.
  • Side cover is removed.
  • Using a power screwdriver, the stoppers are removed from the shock absorbers of the chainsaw, after which its handle is disconnected from the body.
  • Next, you need to remove the drive sprocket and starter.
  • Install the piston stopper in the spark plug hole and loosen the flywheel nut and clutch.
  • Remove the flywheel, clutch and oil pump worm drive mechanism, which is located behind the clutch.
  • Loosen the two screws securing the carburetor and air filter. Remove filter, engine control lever and STIHL carburetor.
  • Remove ignition coil and muffler.

After all these operations have been carried out, it is necessary to clean the saw from dirt again, then turn it upside down and unscrew the four screws securing the engine to the chainsaw body. By unscrewing the screws, the motor is separated from the housing and cleaned again.

On the removed engine, the pallet is untwisted and removed, after which the piston assembly with the crankshaft is removed from the engine.

When removing the piston from the cylinder, you must remember how it was located relative to the cylinder.

Next, using a small screwdriver, the piston pin retaining rings are removed, and the crankshaft is disconnected from the piston.

In the case when it is necessary to replace only the piston, you can install it on the crankshaft, then mount the piston pin circlips, while positioning them so that the snap ring break point is directed downward.

This is necessary in order to exclude the possibility of spontaneous popping out of the circlip during engine operation (according to the STIHL manufacturer’s instructions).

After that, the compression rings are installed, the cylinder is lubricated with engine oil and the engine is assembled.

The work of installing the piston into the cylinder must be carried out with utmost care, since the compression rings are fragile and easily break.

The crankcase is installed on the engine, a sealant is used as a gasket, after which four fastening screws are mounted and tightened crosswise. Further, the engine is installed on the body of the chainsaw. Subsequent assembly is carried out according to the reverse disassembly algorithm.

Replacing a piston on a Chinese chainsaw. Detailed instructions

To be more precise, replacing piston rings (pistons) or a fully piston group on a Chinese chainsaw Forward, Redverg, Patriot, Prorab, etc. with a gradation of engine displacement 45-52 cm³.

Chainsaws of various brands of Chinese production, but approximately similar in characteristics and components, are gaining more and more popularity. The decisive factor in the choice of the buyer in this situation is the price. The low cost of these saws is due to mass production and cheap raw materials. We will not discuss quality and durability in this article.

Let’s consider an example of replacing a piston group on this kind of saws. It should be said that, unlike STIHL and Husqvarna chainsaws, the process of replacing the piston group of Chinese chainsaws is noticeably simplified, in view of the design of these saws.

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 CPG of the chainsaw consists of a cylinder, a piston, a retaining pin and two retainers.

When buying a piston chainsaw, you should pay attention to the inner surface of the cylinder, which must be polished and have a glossy shine. In the presence of damage, scratches, experts do not recommend installing such a cylinder.

In order to increase compression in the working unit and, as a result, increase power, many manufacturers install two piston rings each. Chainsaw compression rings made of special cast iron fit snugly against the cylinder, which ensures the tightness of the combustion chamber.

How to properly install the rings on the piston of a two-stroke scooter

There is nothing difficult in installing rings on the piston of a two-stroke scooter, however, like a four-stroke scooter, and many know this.

But most of the scooters who have only recently acquired such a technique do not even have an idea of ​​how to replace the piston on a scooter, how to properly install the rings on the piston, where the arrow on the piston should look, and much more.

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In this lesson, I will tell you how to properly put the rings on the piston and assemble the piston into place. Since we have already spoken about four-stroke engines before, here we will only talk about two-stroke engines. So, our piston engine is worn out and needs to be replaced.

The rings and the piston are the first to wear out, and usually only need to be replaced. With severe piston wear, the cylinder must be bored. It also loosens when the piston wedges in the cylinder, forming deep scratches on the walls of the latter.

There is nothing wrong with that, and if your new cylinder has gone through the correct bore (for which you will need to pay only about 10), it will need a repair kit of rings with a new piston. Such rings are indicated by marking 0.25.

The second bore is 0.5, respectively, etc. to one.

After purchasing the piston, you need to assemble it. In the kit, as a rule, you will find the piston itself, two compression rings, a third thin corrugated ring (more on its purpose), a piston pin and two piston pin retaining rings.

Now about the third ring in the kit. Its purpose is to spring the lower compression ring. It installs it under it itself, and usually does not have any benefit during operation.

properly, install, piston, chainsaw

Use the saw stop as you slide the chain onto the chain to be properly tensioned. You can throw this ring away, or you can put it, there is no difference.

Quick Tip For Fitting Replacement Piston Rings Into A Chainsaw Engine

Many piston manufacturers do not have one at all.

It’s time to put everything in place. Depending on the scooter model, the compression rings may be the same or differ in thickness and cross-section. Most pistons for Honda scooters, for example, have different rings, where the top is thinner than the bottom and has a different cross-section.

It is imperative to pay attention to this when installing, the top is thinner and sharpened at an angle.

Also pay attention to the inscription on the ring (usually the letter T or the size of the repair), the inscription should always be on top, that is, opposite from the finger. First you need to put on the bottom, then the top. In this case, you do not need to stretch and bend them. These manipulations must be carried out carefully.

There are locks in the ring grooves that prevent the rings from turning during operation, so the ring gap must be exactly in these locks, otherwise you will not stick the piston into the cylinder.

And the last important point is the arrow (1) on the bottom of the piston or the inscription EX. Both the arrow and the inscription must be directed towards the exhaust (2).

In this case, the ring locks will be on the side of the petal valve. How to choose a chainsaw (chain, tire, do you need to press on the chainsaw when cutting.

If the locks are placed in the direction of the exhaust, the piston will not last long, the rings will be pulled into the exhaust window and gradually grind it off.

When installing the piston pin, pay attention to the condition of the cage (bearing), it may need to be replaced.

Before installing the gudgeon pin, install the circlip on one side prior to installing the piston (usually on the side where you will not be comfortable with the pin and second circlip).

Then put the pin with the bearing and the second circlip, when it is fixed in the groove, it will make a certain click.

That’s all, now put on the cylinder, not the piston (remembering to check the condition of the gaskets and lubricating the piston and cylinder walls with engine oil), the cylinder head and tighten the bolts alternately in a crosswise order.

If you have any questions in the process of replacing the piston, you can ask them in the Комментарии и мнения владельцев field or on the forum of our website. How to correctly install the piston on the lawn mower. How. Good luck with the repair.

The procedure for disassembling a gasoline saw:

  • We unscrew the protective cover;
  • Unscrew the candle;
  • Remove the clips from the shock absorbers;
  • We insert a cord into the spark plug hole to hold the crankshaft when unscrewing the clutch and the flywheel nut;
  • Remove the asterisk;
  • Next, remove the carburetor and air filter;
  • We dismantle the ignition block and muffler;
  • We take out the power unit;
  • Remove the oil pan, remove the piston with the crankshaft;
  • Disconnect the retaining rings from the finger;
  • We outline the location of the piston in the cylinder.

Before starting the assembly, it is required to thoroughly clean all the components of the gasoline saw from carbon deposits and dust. Then wipe them with a clean cloth.

Install the piston to the crankshaft. We attach it to the connecting rod with your finger. We install retaining rings on the finger. We put the compression ring on the piston. Lubricate the inner mirror of the cylinder with oil, for better insertion of the piston with a ring into it.

The oil pan is reliably cleaned of dirt and oil. Then we wipe it with a clean cloth moistened with gasoline. Apply heat-resistant sealant to the pallet and fasten.

We assemble the gasoline saw in the reverse order.

How to properly install the piston on a chainsaw?

Replacing a piston on a chainsaw. DIY repair recommendations from the company “Sam Sebe Service”!

Keeping your gasoline saw running at a high level will allow you to use it for years to come. But there are times when it won’t start. After long-term operation, and not only, failure of the cylinder-piston group (CPG) is possible.

In this article we will consider the issues of the need to replace the piston group on a gasoline saw, in which cases this is done and the sequence of operations.

To repair a gasoline saw with a CPG replacement, there must be compelling arguments. As a rule, in such small, high-revving chainsaw engines, the entire piston group changes. Replacing one element, either a piston or rings, usually does not give a stable result.

Description of the piston group of the STIHL 180 chainsaw

On the STIHL 180 chainsaw, the piston group has a diameter of 38 mm. The dimension of the chainsaw CPG is determined by the piston diameter, the cylinder is slightly larger. As standard, the MS 180 CPG is supplied complete with a piston pin, two piston rings and two retaining rings.

The inner surface of the cylinder must be perfectly sanded and have a glossy sheen, which must be taken into account when purchasing a replacement cylinder head for a STIHL ms chainsaw. If there is damage to the inside of the cylinder, it is not necessary to install such a cylinder.

A distinctive feature of the CPG on the STIHL MC 180 is that it has two compression rings, while almost all of its main competitors have only one. According to the manufacturer, the installation of a pair of rings makes it possible to better stabilize the piston in operation, enhance its cooling and increase the compression in the engine, thereby improving starting.

Replacing the piston on the DOLMAR chainsaw

In the repair of a Dolmar 116 chainsaw. If you change the chainsaw not 1. if the piston in the cylinder is not how to dilute the gasoline. Installing the piston. Find out more on our website: Subscribe.

Of course, nothing is eternal, but it is one thing if you change the piston group, after many years of operation and it has worked out its engine hours, fully paid for itself, and another thing is that this saw was refueled, for example, with gasoline, without oil, and it jammed. Fit the STIHL piston correctly. How to put it right. Such a saw has to be repaired, since all other parts are normal.

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Many firms deliberately inflate the cost of spare parts in order to buy new models. Chainsaws and grass trimmers from, for example, STIHL have a wider range of spare parts than Husqvarna. How to correctly install the piston on the lawn mower. And that is why the demand for chain chains for homelite chainsaw and how to find out which one. How. How to put rings on a chainsaw correctly. How right. Therefore, when choosing a certain model, find out how things are with spare parts.

Replacing the piston group in a chainsaw or trimmer

Repair of this level should always be balanced. In such small engines operating at high speeds, replacing one piston that is burned out or jammed does not give a long result and, if necessary, the entire piston group must be changed. Therefore, you need to consider whether to continue using this saw or purchase a new saw.

If this is a professional model, then such a repair is worth doing, but if it is an old household model like the Husqvarna 40 and it has worked for more than ten or twelve years, it is not profitable to repair it. Because its repair will cost, the same as purchasing a new saw, even if not Husqvarna, but for PARTNER P350XT CHROME, the cost of 165 is definitely enough. over, such saws are sold by Husqvarna, since PARTNER is its subsidiary.

But if you do decide to repair your chainsaw or grass trimmer, then you need original spare parts that are not cheap. With proper operation of the engine, the first repair may not come soon and only the piston ring or rings will have to be replaced, depending on the model. Tell me how to put the piston with the ring on correctly. How to put the piston on a chainsaw correctly. How right. But if the saw is jammed, then it is necessary to change the entire piston group. the cylinder, piston and rings.

It should be noted that Husqvarna 136/141 chainsaws have approximately a resource of 500-600 hours, Husqvarna 340/350. 1000-1200 hours, professional chainsaws at least 2000-2500 hours, subject to strict observance of the operating instructions. In fact, it is impossible to rely on these figures, since the real resource can differ significantly, both upward and downward. But roughly we can say that semi-professional saws work 3-4 times longer than amateur saws, and professional ones up to 10 times or more.

Causes of piston chainsaw malfunctions

There are many reasons for the failure of the CPG, which are usually divided into two main categories: natural wear and tear and artificial malfunctions. The first type of malfunction, as the name implies, is the physical wear of the rubbing parts of the piston group. The second category is more extensive and implies:

  • strong overheating of the internal combustion engine and, as a result, the appearance of thermal seizures on the surface of the piston;
  • breakage of the lower part of the piston (skirt) due to the duration of the chainsaw operation at maximum speed;
  • ingress of foreign particles into the combustion chamber and the occurrence of mechanical damage to the CPG;
  • breakage of the compression (piston) ring due to severe wear or exceeding the permissible saw speed;
  • discrepancy between the recommended portions of gasoline and oil when preparing the fuel mixture.

Experts do not recommend disassembling the CPG for no particular reason. However, if the tool has significantly lost power, there is a metallic ringing in the internal combustion engine, or the crankshaft does not turn when the starter jerks, the piston chainsaw should be diagnosed. First of all, to identify engine malfunctions, it is necessary to measure the compression in the cylinder. With a significant deviation from the values ​​recommended by the manufacturer, we can safely say that there are scratches, wear and tear on the surface of the cylinder or piston. It is the drop in compression that is the basis for the complete disassembly and repair of the piston group of the chainsaw.

For the prompt diagnosis of the CPG for a breakdown of the chainsaw compression ring or scuffing in the cylinder, professionals advise to remove the muffler and assess their condition through the outlet window.

An incomplete list of structurally similar chainsaws with the Partner 350 XT chainsaw, which are suitable for the cylinder-piston group of the Partner (Partner) 350, 351 chainsaw (Vityaz):

properly, install, piston, chainsaw

Poulan 2150; Poulan 2250; Poulan 2550; Greenline GL 367; Piran 4016; Piran 350; Piran 351; Packard Spence PSGS 400d; Packard Spence PSGS 450d; Kingston KSCS 4200; McCULLOCH Mac 335; Priority 350; Delta BP-1600/16 / V; Proffer 360; Proffer 361 and others.

We draw your attention to the fact that the Partner 350 chainsaw was produced both with a body on shock absorbers (springs) and in a “rigid” body. Most of the spare parts for these chainsaws are absolutely similar, but some elements have slight differences, please take this into account when choosing spare parts for chainsaws Partner 350 XT and its analogues.

Algorithm for replacing a piston chainsaw

If it is time to replace the CPG of the chainsaw, you need to know that for each specific model there is an individual algorithm of actions. To facilitate disassembly / assembly work, you must prepare a spark plug wrench, a large flat screwdriver, a hammer, a compressor for cleaning the unit parts, a set of open-end and socket wrenches. Regardless of the manufacturer and design features of the model, before removing the cylinder of the chainsaw, the following work must be performed:

  • Dismantling the upper protective cover;
  • Unscrewing the spark plug;
  • Removing the side cover;
  • With the help of a large flat screwdriver, the stoppers are removed from the shock absorbers;
  • In the channel of the candle we place a lace to fix the crankshaft and unscrew the clutch and flywheel nut;
  • Dismantling the drive chain sprocket;
  • We remove the carburetor with an air filter;
  • Removing the ignition module and exhaust system.

After removing it from the base of the power unit, unscrew the pallet and remove the crankshaft with the piston from the cylinder. Using plumbing tweezers or a screwdriver, we dismantle the piston pin stoppers.

Before dismantling the piston, it is necessary to remember its location in the cylinder, so that later you do not waste time on re-disassembling and assembling the power unit.

Chainsaw pan sealant

Before starting the assembly, it is necessary to clean the parts and assemblies of the unit from dirt, sawdust residues, dust with compressed air, rags and other means. The first step in replacing a piston chainsaw is to install a piston on the crankshaft. We fix it on the connecting rod with a steel pin included in the delivery set of the CPG. In order to prevent arbitrary falling out of the retaining rings, it is recommended to install them with a cut down. Next, we mount the compression rings on the piston, but due to their fragility and fragility, this operation must be approached as carefully as possible. To prevent the formation of scratches before installing the piston in the cylinder, the piston must be lubricated with oil. Before installing the crankcase (pallet), you will need to degrease its mounting surface and apply a layer of heat-resistant sealant. We assemble the chainsaw in the reverse of the algorithm described above.

Often, replacing the chainsaw piston, crankshaft and compression rings solves problems with idle speed and problematic starting of the internal combustion engine.

Chainsaw Partner 371. Replacing the piston group

Chainsaw Partner 371. Replacing the piston group.