How to change a piston on a chainsaw

Why the Stihl chainsaw won’t start after replacing the piston

If the saw does not start after replacing the piston saw, it is necessary to check the fuel supply to the chamber, as well as to diagnose the ignition system. Very often, when installing the control lever on the chainsaw, the craftsmen forget to connect the wires coming from the ignition coil, as a result of which the spark disappears and the saw does not start.

Also, the problem may lie in a pinched fuel supply hose or if it is not connected at all. Of course, there can be many reasons, but it is worth remembering that if all the work on replacing the piston is carried out correctly, the tool should start without any problems and work normally.

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 to have 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.
  • Unscrew the two screws securing the carburetor and air filter. Remove the 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.

change, piston, chainsaw

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, and then mount the piston pin circlips, while positioning them so that the break point of the circlip 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 manufacturer’s instructions Stihl). 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 performed according to the reverse disassembly algorithm.

How to change a piston on a Stihl 180 chainsaw

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.

  • When a piston needs to be replaced
  • Description of the piston group of the Stihl 180 chainsaw
  • How to change a piston on a Stihl 180 chainsaw
  • Why the Stihl chainsaw won’t start after replacing the piston
  • Video
  • Outcomes
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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 reciprocating saw on it. Also in the video you can see how the saw is cleaned correctly during the repair process.

When a piston needs to be replaced

There can be quite a few reasons why the piston needs to be replaced, as well as a completely piston one, but they can all be divided into natural and resulting from improper operation. Natural, this is the wear resulting from the long-term operation of the Stihl 180 chainsaw. There are much more artificial ones, for example:

  • overheating of the engine and the appearance of thermal seizures;
  • ingress of a foreign body into the cylinder and the appearance of mechanical scoring;
  • breakage of the piston ring as a result of exceeding the maximum engine speed;
  • breakage of the piston skirt due to overspeed;
  • the use of low-quality fuel, as a result of which the piston group of the chainsaw wears out from the side of the intake channel in the cylinder;
  • operation of a Stihl chainsaw with a dirty fuel filter, as a result of which the percentage of oil in the fuel mixture is reduced;

It is necessary to diagnose the CPG if the Stihl ms 180 suddenly lost power or does not start, while the starter of the tool does not turn. If the starter cranks, but the saw does not start, while there is a spark and the fuel enters the cylinder properly, it is necessary to measure the compression in the engine.

If there is a suspicion of problems with the CPG, it is advisable to contact a service center authorized by the manufacturer, since only there they can accurately diagnose the malfunction without full analysis and, if necessary, carry out a high-quality repair.

9.5. 11 atm. It is considered a normal indicator at which the Stihl chainsaw starts up properly and delivers maximum power, if the compression is lower, there is a possibility that there are scuffs on the cylinder-piston group, or its wear is quite large. In any case, with reduced compression, for further diagnostics, it is necessary to completely disassemble the saw.

It is possible to determine the presence of scoring on the piston, as well as the breakage of the piston ring, if you remove the muffler and conduct a visual inspection of the visible part of the piston, while the rings can be checked for elasticity by pressing on them with a small screwdriver. There will be slight movement on the working rings, a defective or jammed piston ring will not move.

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 buying a spare cylinder piston 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.

We examined the main causes and malfunctions of the Stihl ms 180 chainsaw in which it is necessary to replace the CPG. But, as a rule, in each specific case, the reasons may overlap, and for proper repair, an integrated approach to solving the problem is required. Putting a new reciprocating saw on the saw does not always mean solving the problem. It is imperative to eliminate the causes of the malfunction and the tool will serve for a long time without problems and the need for repair.

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Do-it-yourself chainsaw repair: analysis of major breakdowns and methods for their elimination

It would seem, why does a chainsaw need a summer resident who grows vegetables and fruits, or the owner of a country house who has a small garden and several flower beds? The question disappears when there is a desire to build a bathhouse, update a greenhouse, knock down an old business, or just make a bench for relaxation. Unfortunately, any mechanism periodically needs prophylaxis and replacement of spare parts, and for this you need to be well versed in the device of the product, in addition, repairing the chainsaw with your own hands will save time and money.

Checking the fuel supply system

In the previous section, one of the reasons for the lack of fuel supply to the cylinder was already mentioned. a dirty fuel filter. It is checked by the intensity of the jet from the fuel hose, weak. the filter needs to be cleaned, and in case of severe wear, it must be completely replaced. Prophylactic replacement is recommended every three months.

Poor fuel outflow may mean a clogged tank cap breather. Cleaning is done with an awl.

Another sign of a problem is a lack or poor supply of the fuel mixture. This is due to several possible reasons:

  • contamination of the air filter (washing and subsequent drying);
  • problems with the carburetor. one of the options is possible: settings failure, damaged membrane, clogged channels.

The possibility of regulating the carburetor by the townsfolk is minimized. adjusting the idle speed. But even the correct setting of the latter will significantly increase the power of your chainsaw. Plus, an incorrect factory setting is possible, the latter is evidenced by:

Part 4: Stihl chainsaw piston and cylinder replace / repair. 026 MS260

  • increased vibration and damaged protective cap;
  • harmony of the cylinder-piston group;
  • clogging of the carburetor;
  • impossibility to start and instant stop after start;
  • drop in performance with increasing consumption of the combustible mixture.

The adjustment takes place in two phases: basic, with the engine off and finishing. with the engine running, pre-warmed up. Adjustment is carried out with adjusting screws, with basic adjustment screws “L” and “H” are used, the third one. “T” is not touched yet. We wrap them up to the end, and then 1.5 turns in the opposite direction. During the final adjustment, turn the screw “T” counterclockwise to achieve minimum RPM. The engine must run stably, the chain must remain in place. If, after adjustment, the engine stalls. you need to return the screw to its original position, the chain continues to move. then unscrew the screw. Testing debugging with:

  • acceleration. speed should be gained quickly;
  • the maximum number of revolutions. in case of interruptions in the ignition, loosen the screw “H”;
  • idle operation. the chain should not move, the speed should be gained as quickly as possible.

Additionally, use the instructions to properly debug the carburetor mechanism.

DIY piston chainsaw repair

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 speed and the consumption of the fuel mixture.

Replacing the piston group on the Stihl MS180 chainsaw

In this video we will show you how to replace the piston group on the Stihl MS180 chainsaw, crankshaft oil seals.

A distinctive feature of the CPG on the Stihl MC 180 will be that it has two compression rings installed, although in fact all of its main rivals have only one. As the manufacturer convinces, the installation of a pair of rings makes it possible to better stabilize the piston in work, enhance its cooling and increase the compression in the engine, which is why starting is improved.

Chainsaw structural components

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

To begin with, we suggest that you familiarize yourself with the video clips that show how the chainsaw works and how it works:

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

  • Stops to start;
  • Starts up, but soon stops;
  • Ceases to function in the cut;
  • Loses its power;
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Most of the malfunctions are associated either with interruptions in the operation of the engine (fuel supply system, exhaust system, ignition, cylinder-piston part), or with malfunctions of other systems and assemblies (clutch, chain brake, tire, lubrication system). Consider the most common breakdowns and techniques for their elimination.

A serviceable chainsaw starts with one jerk and does not fail in the cut

Chainsaw breakdown typology

Before disassembling the chainsaw, you need to correctly determine the type of breakdown. Any malfunction in the saw operation conditionally refers to one of two types. The first is engine breakdown. Problems arise in ignition systems, fuel supply, air supply, exhaust air mixtures, cylinder-piston group.

The second type is malfunctions in other systems of the unit. These are breakdowns of the emergency brake, clutch, guide bar, lubrication system and other parts.

Repair tool kit:

  • keys of different sizes;
  • key for removing spark plugs;
  • screwdrivers of various sizes and shapes;
  • saw circuit.

Tips for dismantling different components and systems

Within the scope of this article, only general recommendations can be given, since chainsaws from different manufacturers may have significant technical differences.

Before disassembling a faulty tool, it is necessary to dismantle the saw headset, drain fuel and oil from the refueling tanks, clean the hard-to-reach places of the chainsaw from surface contamination.

When a piston needs to be replaced

There can be quite a few reasons why the piston needs to be replaced, as well as a completely piston one, but they can all be divided into natural and resulting from improper operation. Natural, this is the wear resulting from the long-term operation of the Stihl 180 chainsaw. There are much more artificial ones, for example:

  • overheating of the engine and the appearance of thermal seizures;
  • ingress of a foreign body into the cylinder and the appearance of mechanical scoring;
  • breakage of the piston ring as a result of exceeding the maximum engine speed;
  • breakage of the piston skirt due to overspeed;
  • the use of low-quality fuel, as a result of which the piston group of the chainsaw wears out from the side of the intake channel in the cylinder;
  • operation of a Stihl chainsaw with a dirty fuel filter, as a result of which the percentage of oil in the fuel mixture is reduced;

It is necessary to diagnose the CPG if the Stihl ms 180 suddenly lost power or does not start, while the starter of the tool does not turn. If the starter cranks, but the saw does not start, while there is a spark and the fuel enters the cylinder properly, it is necessary to measure the compression in the engine.

If there is a suspicion of problems with the CPG, it is advisable to contact a service center authorized by the manufacturer, since only there they can accurately diagnose the malfunction without full analysis and, if necessary, carry out a high-quality repair.

9.5. 11 atm. It is considered a normal indicator at which the Stihl chainsaw starts up properly and delivers maximum power, if the compression is lower, there is a possibility that there are scuffs on the cylinder-piston group, or its wear is quite large. In any case, with reduced compression, for further diagnostics, it is necessary to completely disassemble the saw.

It is possible to determine the presence of scoring on the piston, as well as the breakage of the piston ring, if you remove the muffler and conduct a visual inspection of the visible part of the piston, while the rings can be checked for elasticity by pressing on them with a small screwdriver. There will be slight movement on the working rings, a defective or jammed piston ring will not move.