How to check a piston on a chainsaw

Why did the piston burn out?

Husqvarna chainsaw won’t start

If your Husqvarna won’t start, the first thing to be sure is that you are following the saw start sequence and that there is fuel in the tank. Detailed instructions on how to start and refuel a cold saw can be found in the saw instruction manual that comes with all Husqvarna chainsaws.

In the event that you do everything correctly, but the saw does not respond, the reason may be a malfunction of the ignition system or the lack of fuel supply.

For a more accurate determination of the reasons for this behavior of the chainsaw, it is necessary to inspect the spark plug, and then check it for the presence of a spark.

If the spark plug is wet, and when checking the spark, it was not found, it is worth trying to replace the plug itself. The replacement did not give results, which means that the problem may be hidden in the ignition coil, which is quite difficult to check on your own.

How To Check For a Scored Piston Chainsaw STIHL 028 AVS WOOD BOSS

In the event that there is a spark, and the spark plug is dry, there are problems in the fuel system. To eliminate it, you need to carry out its full diagnostics. The fuel system consists of a carburetor and a fuel line. Without some experience, it is possible to check the fuel line for leaks, as well as the cleanliness of the fuel filter installed in the tank. It is better to entrust the full diagnostics and repair of the carburetor to professionals.

Chainsaw chain is spinning at idle speed

If the Husqvarna chain rotates at idle, then it can be concluded that there are malfunctions in the clutch mechanism or the idle is not adjusted. To eliminate the malfunction, it is necessary to remove the saw chain brake cover and inspect the integrity of the clutch spring. Replace defective clutch.

If the clutch is working properly, to eliminate chain spin, it is necessary to correct the idle speed using the adjusting screw marked with the letter (T) or carry out a full carburetor adjustment.

Important: a possible reason for an independent increase in idle is the appearance of air leakage into the engine crankcase or carburetor, which can lead to serious damage to the CPG

Piston burned out: reasons and what to do

The study of various piston damages shows that all causes of defects and breakdowns are divided into 4 groups:

  • interruptions in cooling
  • imperfect lubrication
  • immoderately large thermo-force influence from the gases in the combustion chamber
  • mechanical problems.

At the same time, many causes of piston defects are interrelated, as are the functions performed by its various elements. In particular, defects in the sealing belt cause overheating of the piston, damage to the fire and guide belts, and scoring on the guide belt leads to a violation of the sealing and heat transfer properties of the piston rings.

check, piston, chainsaw

Ultimately, this will most likely provoke burnout of the fire belt.

Other reasons

How do you diagnose a saw?

The reasons for turning off the chainsaw are not always on the surface. If all of the above methods did not help, there remain other options for malfunctions.

The following elements are subjected to diagnostics:

Compression in the cylinder.

Compression in the crankcase.

Kulikov Vladimir Sergeevich

Users who are poorly versed in the saw device are not recommended to conduct a deep inspection on their own. Rough handling can cause serious damage to the tool.

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The reasons for the breakdown of the carburetor are different:

  • Loosening of the retaining screw.
  • Gasoline leaks.

Air suction into the cylinder.

To assess the condition of the carburetor, it is recommended to show the tool to a service center. Preference is given to branded centers, whose specialists know about the peculiarities of the unit of a particular manufacturer.

Despite its imposing appearance, the chainsaw is a fragile tool to which it is important to find the right approach. For correct operation, it is important to supply the saw with high-quality fuel and prevent it from stagnating in the tank.

In order not to be left in a hopeless situation, it is advisable for the owner of the chainsaw to get acquainted in detail with the structure of the unit and its internal elements.

Bad gasoline

Hydraulic gasoline burns the piston for the same reason. as a result of overheating. Because the gasoline that we pour into our gas tank often cannot be called gasoline. Correct gasoline burns at a sufficiently low temperature, while expanding very vigorously, because the essence of any gas driven into top dead center (TDC) is that it expands as much as possible relative to its original volume, thereby pushing the piston downward with maximum conviction, and combustion and emitted temperature are all side effects that the engine would be pretty cost-effective without. In bad gasoline, as in normal gas, there are components such as benzene, gasoline and other bad substances. The fact is that they are contained in low-quality “gasolines” in absolutely different proportions, but actually in larger proportions than the standards allow.

Chainsaw muffler malfunction

It often happens that during prolonged operation, the walls of the exhaust pipe are covered with carbon deposits, which prevents the free exit of exhaust gases. In this case, remove the muffler (if possible) and wash it with detergents, then dry thoroughly with a hairdryer.

ATTENTION! Carbon deposits contain carcinogens. During dry cleaning, it can enter the lungs and pose a threat to your health.

Carbon deposits are usually caused by an incorrect gasoline-oil ratio or the use of low-quality and incompatible oil. Carefully read the instructions for use of the chainsaw to prevent this from happening in the future.

Repairing the chain lubrication system

Let’s consider three main faults:

  • Oil leakage. Check that the pipes are tightly connected to the pump unions and that they are not cracked. Problem tubes are sealed with sealant or replaced.
  • Insufficient oil supply. Most likely, the lubrication channels are clogged.
  • Cracks in the oil pump housing. Part needs to be replaced.

The material on how to sharpen a chainsaw chain will also be useful:

Here’s how to diagnose the lubrication system:

Chainsaw design

All saws on a gasoline engine are structurally similar, so the causes of breakdowns are the same for both the expensive European Husqvarna unit and the popular cheap Chinese Champion 137 chainsaw. Do-it-yourself repairs can be carried out only with knowledge of the elementary laws of physics, the ability to read diagrams, drawings, and the presence of skills in working with mechanisms.

So, the chainsaw consists of:

  • engine (mainly single-cylinder, two-stroke, carburetor);
  • functional part (saw part with chain);
  • service systems (starter, carburetor and other mechanisms).

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 CPG of the chainsaw is determined by the diameter of the piston, the cylinder is a bit difficult. In the complete set, the standard CPG MS 180 is supplied complete with a piston pin, 2 piston rings and 2 retaining.

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The inner surface of the cylinder must become completely polished and have a glossy shine, where you need to direct attention when purchasing a spare CPG for the Stihl ms chainsaw. If there is damage to the inside of the cylinder, there is no need to install such a cylinder.

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:

  • 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.

Fuel supply system repair

Fuel may not enter the cylinder for the following reasons:

  • Dirty fuel filter. Remove the fuel hose and check how the fuel flows. If the jet is weak, the filter may need to be cleaned. 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 tank cap). Check also 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 a clogged air filter. Air ceases to flow into the carburetor in the required amount, in this regard, due to a too rich fuel mixture, engine operation is disrupted. The contaminated filter is carefully removed, cleaned and washed in water, then dried and reinstalled.
Read more:  How to Clean a Chainsaw Air Filter

Another reason is improper adjustment of the carburetor. Adjustment is made with three screws.

Timely replacement of the fuel filter ensures full fuel supply

The fuel hose and choke actuator must fit snugly against the fittings

The throttle lever cable must be in place

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

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 parts.

All parts must be clean, dry and in good condition.

How to increase the life of your chainsaw

You need to have a couple of tires and at least four chains in reserve. For a uniform wear process, the chain must be turned 180 ° after three hours of operation, after the same period of time, the chain must be replaced with another.

Timely cleaning of the tool ensures that the various holes are not clogged, which can lead to difficulty or even stop the flow of the fuel mixture, which will affect the working condition of the chainsaw.

If you are not confident in your abilities and are afraid to spoil the unit, then it is better to contact the professionals. They, by virtue of their experience, will always be able to correctly diagnose the problem and qualitatively fix the problems in your chainsaw.

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.

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.