What compression should be in a chainsaw

Table of Contents:

How much compression should there be in the Husqvarna chainsaw?

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

Engine malfunctions

  • the engine will not start;
  • starts up, but stops;
  • the engine won’t start; it won’t start; it won’t work stable;
  • no power, t.е. runs fine at idle speed but stalls under load.

Doing the repair of chain saw with your own hands, you need to act in the way of elimination. check all probable causes of malfunction, starting with the ones that take the shortest time to check and fix (about the structure and operation of the two-stroke motor, see here).

Almost all types of engine malfunctions listed above can be caused by ignition system failures. That’s why it makes sense to start troubleshooting with the spark plug. This is all the more justified, as the condition of the latter can give useful information about the work of the fuel system. So, if there is a problem, 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, the problem is probably not in the ignition system, but in the lack of fuel mixture in the cylinder. You can screw the spark plug back in and take care of the fuel system. If the spark plug is heavily spattered with fuel mixture, it means that there is excessive fuel mixture. It could be because the carburetor is out of adjustment or a faulty startup. How to measure the compression in a scooter correctly. The plug is wiped and dried, the cylinder is drained by cutting off the fuel supply and working with the starter. to ventilate the combustion chamber and remove the excess fuel. Then put the spark plug back in place and repeat the start.

The presence of a large amount of black sludge also indicates a faulty fuel system.

Maybe the oil to gasoline ratio in the mixture is off, the carburetor is not adjusted, or low-quality oil is used. The spark plug is washed in gasoline, cleaned of carbon deposits with a needle or awl, the electrodes cleaned with a fine cloth and refitted.

In all these cases, it is not superfluous to check the gap between the electrodes of the plug. Depending on its brand, it should be in the range of 0.5-0.65 mm. It is also necessary to check the gasket of the plug. If it is worn or damaged, the sealing of the combustion chamber can not be ensured, which leads to decreased compression in the cylinder and engine problems.

Even if there is great reason to believe that the problem is in the fuel system, you should check the spark plug for. If only to be sure that everything is all right. To do this:

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

If there is no spark, you just need to replace the spark plug. If even a new spark plug has no spark, you need to check the condition of the high-voltage wire for breaks and contact with the spark plug.

HOW to measure compression chainsaw 4500

the customer says the spark plug does not start and there is no spark. Looking for causes.

When you measure the compression with the choke open, the picture will be different. A large amount of incoming air and an increase in pressure in the cylinder, of course, contributes to the leakage. They are, however, notoriously less than the air supply. As a consequence, the compression does not drop that much (to about 0.8-0.9). Therefore, measuring compression with an open valve is better suited to determining the more “rough” engine defects, such as piston failure, ring coking, valve burnout, cylinder surface scoring.

In both methods of measurement, it is desirable to consider the dynamics of pressure growth. it helps to establish the true nature of the fault with greater probability. So, if on the first stroke the value of pressure measured by a compressometer is low (0.3-0.4), and during the following strokes it increases sharply. it indirectly testifies about wear of piston rings. In that case, pouring a little oil into the cylinder will immediately increase not only the pressure in the first measure, but also the compression.

How to check the engine compression?

The most common tool for this purpose is the aforementioned compressometer. In contrast to the unpretentious domestic designs, foreign companies produce the whole set with a set of adapters, allowing to measure on all brands and models of cars.

Modern engine testers measure the compression quickly and efficiently. These devices do not actually measure the pressure, but the amplitude of the pulse of the electric current consumed by the starter during cranking. in fact the higher the pressure in the cylinder, the higher power consumption of the starter to rotate the crankshaft. Thus, it is possible to measure the compression in all cylinders simultaneously in just a few revolutions, without having to unscrew the plugs, which is particularly important for multi-cylinder engines.

The disadvantage of the engine tester is that the results are expressed in relative units, for example, as a percentage of the cylinder running better. Only the most expensive engine testers are able to measure the absolute compression value in each cylinder, but this is only possible on the basis of a large number of model-specific statistics and their comparison with the actual cylinder pressure.

A chainsaw is a simple device that, with proper care, will last a long time. A chainsaw is, however, a tool that is subject to different stresses and, therefore, breakdowns do occur. About what caused a certain malfunction and how to fix it, you will learn from this article.

How to properly run-in a chainsaw. the main threats

What, in fact, are the problems of many tips. Let’s break it down one by one.

# n/a Advice encountered The pros Arguments “against”
1 The chainsaw should be run in idle mode. RPMs are lowest at idle. The most damaging of the encountered tips. A great way to kill the cylinder-piston group. Idling, even in cars, is allowed only for a short time: in this mode, the fuel does not burn in optimal proportions, degrades sharply the possibility of lubricating the surfaces, heat sinks sharply, carbon deposits appear, and in the long mode, scuffing occurs.
2 It is necessary to prepare a special mixture of oil and gasoline for the chainsaw. In a special proportion (some websites say more oil, some say more gasoline). Arguments “Pro” offer both. The one who listens to the advice of “experts” decides which oil to use. Deviating from the manufacturer’s instructions leads to imminent problems from either oil starvation or over-lubrication. No good will come of either.
3 You should carefully study the instructions, prepare the mixture, pour the oil into a container to lubricate the chain and work carefully. “In favor because it is the manufacturer’s recommendation. There are no arguments against. But why do so many sites have to spell out this triviality in a dozen paragraphs?? To make this article lengthy?
4 Use the “H” adjusting screw to lower the chainsaw’s minimum rpm and make the mixture richer. Low RPMs improve lubrication. This is the recommendation of the “leading saw manufacturers”. This is not true. No manufacturer would recommend that you fill your saw with oil and thus try to pass on the inadequacies of your own production to the customer.
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There are other variants of advice. It is impossible to list everything.

The design of the chainsaw and the general classification of malfunctions

The main condition for successful repair is proper diagnosis. Therefore, in order to determine why the chainsaw failed and, most importantly, how to make it work again, first of all, you need to know the features of its construction.

It should be noted, it is not particularly difficult, as it includes:

  • Engine (two-stroke gasoline engine);
  • functional part (saw bar and chain);
  • systems that make the two components work together (ignition, filtration, lubrication, etc.).д.), that is, the tool as a whole.

In order to simplify the diagnosis of faults it is customary to distinguish them into two main categories:

Most of the malfunctions are in the engine systems, but the other parts of the tool can fail at any time due to intensive use or improper maintenance. How to determine where exactly the fault occurred? A simple logic will help us.

If the problem is in the engine, it will:

As for all other faults, as a rule, they reveal themselves during normal operation of the motor.

Why the running-in period is necessary

Initially, the idea underlying the necessity of this process seems logical and correct: it is necessary so that the surfaces of the parts moving relative to each other are rubbed to each other. The result:

  • The power increases;
  • The lubrication capabilities of the components are improved;
  • There is less wear and tear;
  • Noise is reduced;
  • the heating and, consequently, the risk of loss of strength properties of the surface and the geometry of the structure.

And it’s true, if you make an excursion to a typical machine-building plant, you can see that the manufacturing processes for, say, pistons and cylinders, are not so perfect. There are always rough spots that just need to be lapped. But the trouble is that at this point there are a lot of advisers who start advising the devil.

What to do if the Partner 350 chain saw will not start?

Now that you know what’s causing the problem, it’s time to get down to business. A faulty ignition system can only be repaired by taking it apart. To do this, remove the remaining fuel from the tank. Then carefully disconnect the wire and remove the spark plug (a special key is provided for its extraction).

  • Test it to see if it works. To do this, put the ignition cable on the spark plug, and connect the nut of the plug and the cylinder with pliers. Now start the starter. You’ve got a spark? Then the spark plug is in working order. No spark? So, to resuscitate the spark plug is not possible, and it must be replaced. And what you can do with a working spark plug? Even the appearance of the spark plug is an indication of the repair method.
  • The spark plug is completely dried out. This means that it is not wetted by the fuel mixture. The problem is to be found at the fuel inlet in the cylinder, the fuel is malfunctioning. The spark plug and ignition system in general have nothing to do with it. Replace the spark plug and look for the real cause.
  • The spark plug is excessively primed with fuel mixture. The first thing to do, of course, is to wipe it down with a napkin and put it aside. You might now be looking for a carburetor misalignment. While the spark plug is air drying you can turn off the fuel and turn on the starter to check the combustion chamber. After a few minutes, the spark plug can be installed in its place in the mechanism and the chain re-started.
  • The spark plug has a layer of soot on it. Fouling is caused by improper fuel mixture. There are two possibilities: either you saved some money and fueled the chain saw with low-quality gasoline, or the gasoline and oil mixtures are mixed incorrectly. The spark plug should be cleaned properly. To remove the fouling plug, a needle, thin awl or similar tool from handy tools will do. The electrodes also need to be cleaned.

In addition, in any case, it will not hurt to make sure that the carburetor is properly adjusted chainsaw. Don’t start adjusting until the air and fuel filters are clean. If the filters are fine, use the adjustment screws.

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

Engine malfunctions

Doing the chainsaw repair with your own hands, it is necessary to act in the way of exclusion. check all possible causes of problems one by one, starting with the ones that take the shortest time to check and correct (about the construction and operation of a two-stroke motor, see here).

Ignition system. Almost all of the types of engine problems listed above can be caused by ignition system failures. That’s why it makes sense to start troubleshooting with the spark plugs. This is all the more justified, as the condition of the latter can give useful information about the operation of the fuel system. So, if the problem occurs, it is necessary to unscrew the spark plug and look at it.

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

If the spark plug is dry, it means that the problem is most likely not in the ignition system, but in the lack of fuel mixture in the cylinder. You can screw the spark plug back in and start working on the fuel system. If the spark plug is heavily spattered with fuel mixture, it means that there is an excess of fuel. It could be due to a carburetor misfire or a failure to start the engine properly. How to measure the compression on your scooter properly. Wipe and dry the spark plug, dry the cylinder by cutting off the fuel supply and running the starter. to ventilate the combustion chamber and remove the excess fuel. After that put the spark plug back in place and repeat the start.

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

The oil to gasoline ratio in the mixture may be wrong, the carburetor is not adjusted or low-quality oil is used. The spark plug is washed in petrol, cleaned from sludge with a needle or awl, the electrodes are finely sanded and refitted.

In all these cases, it is worth checking the gap between the electrodes. Depending on its brand, it must be in the range of 0.5-0.65 mm. It is also necessary to check the spark plug gasket. If it is worn or damaged, the combustion chamber may not be sealed, which leads to reduced compression in the cylinder and problems in engine operation.

Even if in the case of a spark plug check there are good reasons to believe that the problem is in the fuel system, it is necessary to check the spark plug for the presence of spark. At least just to be sure that there is nothing wrong with it. To do this:

If there is no spark, simply replace the spark plug. If even a new spark plug has no spark, you should check the high-voltage wire for breaks and contact with the spark plug.

The absence of spark can also be caused by a defective ignition module or a gap between the module and the flywheel fuse. It should be at 0.2 mm. A gap is especially likely to be present if the saw has been disassembled and the handwheel and ignition module removed beforehand. What malfunctions are possible in a chainsaw, and how do you check the compression and. Adjust the gap with the help of a spacer of thickness 0.2 mm placed between the flywheel boss and the ignition module. The defective ignition module must be replaced.

After checking the ignition system in this way and finding no fault, you can move on to the fuel mixture system.

Fuel system. If the examination of the plug was found that the fuel does not enter the cylinder, you need to consider all possible causes of this. It could be:

To diagnose the first two causes, it is enough to disconnect the fuel hose from the carburetor and see if fuel is leaking out of it or not. If it leaks a full stream, the breather and filter can not be checked, if it does not leak or leaks weakly, you can consider that the cause of malfunction is found. The breather plug is cleaned with a needle. The fuel filter is removed through the filler hole of the emptied fuel tank, with a wire hook, together with the suction hose, from which the filter is disconnected and cleaned or replaced with a new. Chainsaw manufacturers recommend changing the fuel filter every 3 months.

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How to Fault a Gasoline Piston on a Chainsaw

Checking compression on the Campion 254 chainsaw Video commentary for Anton Rogachev.

Insufficient flow of fuel mixture from the carburetor to the cylinder or a disturbance of the correct ratio between fuel and air mixed in the carburetor can occur for several reasons: due to a clogged air filter, unadjusted carburetor, clogged channels or filter screen.

As a rule, chainsaw repair does not do without cleaning the air filter, because it gets dirty rather quickly. When this occurs, the air flow to the carburetor is reduced and the fuel mixture at the carburetor outlet is over-enriched, which disrupts normal engine operation. Dirt filter should be carefully removed for cleaning so that it does not get into the carburettor. The filter should be cleaned or washed in water with some detergent, dried and put back in.

The carburetor is not properly regulated. This is usually done with three screws. Check the engine oil level and revolutions for maximum and minimum and the idle speed screw. Adjustment should be carried out in strict accordance with the instructions, failure to comply with which can lead to engine failure. Some saw manufacturers leave only one adjustment screw (idle speed). to prevent inexperienced users from tampering with the carburetor. How to measure the compression in to check it you can futlik there is a breather on this chainsaw? In all these cases, it is not unreasonable to check in the cylinder and how the compression in. See an example of adjusting a chainsaw carburetor in the article Working with a chainsaw.

If adjustment of the carburetor has not helped, it is necessary to clean its channels and the filter grid, and at the same time to check the integrity of the membrane. Carburetor. one of the most complex devices of a chainsaw, so to start its disassembly and cleaning should be fully aware of the responsibility of this operation. It consists of many small parts, which have a feature to unnoticeably pop out of their places and irrevocably lost, so that, after disassembling this capricious device, you can not collect it.

How to check compression on a chainsaw

Today almost every villager or dacha owner has a chainsaw. They are in high demand because they are easy enough to operate. Even if it breaks down, the saw can be repaired with your own hands, although it may take a long time. In the household, consumers use household or semi-professional (farm) saws, which are designed for a small front of work.

Basically, all chainsaws are equipped with a two-stroke carburetor engine with one cylinder and air cooling. Stability of operation depends directly on the carburetor, which prepares the fuel-air mixture. The air entering the engine must be free of dust and other impurities that could clog it, otherwise the piston group would wear out rather quickly.

To prevent this, the chainsaw’s air filter must be cleaned regularly. The chainsaw has an air precleaner to prevent the air filter from clogging up more seldom.

The engine is started by a starter (a rope with a crank wrapped around a pulley). Modern saws, even low-powered ones, are equipped with mechanisms to make starting easier. These include:

The chainsaw can vibrate a lot when working, so it is equipped with an anti-vibration system to dampen vibrations. The handles of the saw are connected to the engine by means of a damper (a rubber gasket or a steel spring).

The sawing part of the chain consists of a cutting chain around the edge of the bar, a sprocket and a chainwheel.

Filters

A “rich” or “poor” fuel mixture will sooner or later cause a breakdown. Possibly even expensive. To prevent this from happening, it is not unreasonable to check the filter regularly for scuffs, as well as a breakdown of the filter blade itself.

How to check and replace the fuel filter

To check the current condition of the fuel filter, proceed as follows:

If the gasoline is coming in unevenly and jerkily, it’s time to put in a new filter element. This is quite easy to do:

  • Unscrew fuel tank cap.
  • Use tweezers or any other device to remove the filter itself.
  • Disconnect the old filter and put a new one in the fuel tank.

How to Clean the Air Filter

If not enough air is available, the fuel mixture becomes over-enriched, which causes the engine to malfunction. Regularly purging the air filter, and in especially severe cases, flushing it with soapy water will avoid these problems.

Malfunction of an undefined category

In a number of cases chainsaw owners have to solve more complicated problems to fully restore the functionality of their cutting tool.

Chainsaw does not develop full power

In addition to the problem discussed above with a lack of gasoline or air flow into the cylinder, the cause of weak power may be a clogged muffler.

If you do not periodically clean a clogged muffler, the problem of poor engine power may not be the only.

Leaky carburetor and clogged nozzle

Over time, the screws that secure the carburetor cap can become loose or the gaskets can fail. A clogged filter or its unskilled replacement can lead to clogged nozzles. All this also adversely affects the performance of the chainsaw and reduces the service life.

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

Your chain saw does not hold idle speed

It often happens when, after long transportation and constant use, the chainsaw refuses to run smoothly at idle speed. As a rule, this problem is eliminated by adjusting the carburetor.

To learn how to properly debug a carburetor, read the following

If the carburetor is tuned like clockwork, you need to check it:

  • Fuel system. The fuel pump is a good place to start.
  • Muffler. There is a high probability that the engine cannot function properly because of the accumulation of soot.

Chainsaw loses power under load

If the saw’s power is lost somewhere in the process, you should look for the problem in the following places:

What Compression In A Chainsaw

Chainsaw. It’s a simple device that can last a long time with proper care. In this case, the saw is a tool that is subjected to various stresses, and, therefore, there are still breakdowns. In this article, you will learn what caused a particular problem and how to fix it.

Basic Skills and Tools for Repair

Most chain saw malfunctions can be repaired with your own hands. However, this requires an understanding of the chainsaw and how the components function together. As far as the tool is concerned, it is often necessary:

Repair it yourself or send it to a service center

It should be understood that not every problem can be solved on its own. Not every chainsaw owner has a compressor at home or a special device that can create a vacuum and the right pressure, for example, to check the tightness of the crankcase. In this case, you simply can not do without turning to specialized professionals.

Troubleshooting Algorithm

If you are confident that you can disassemble the chainsaw after disassembly, there is a screwdriver in your hand. To determine the true cause of the malfunction, you need to analyze the condition and behavior characteristics of the saw.

How to check the crankshaft seal

The presence of packing leaks can only be checked by reaching the crankshaft and carefully inspecting it for leaks. You can learn how to do this properly in

How to put a piston on a chainsaw

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

  • Top and side covers removed.
  • The spark plug is screwed in.
  • They are removed from the shock absorbers from the plug, and the handle is detached from the housing.
  • The master sprocket and starter appear in the film.
  • The piston stopper and the nut for securing the flywheel and clutch are installed in the spark plug hole.
  • Flywheel, clutch, worm gear oil pump, located directly behind the clutch mechanism, are removed.
  • The carburetor and air filter mounting screws are unscrewed, and then these components are removed along with the engine control lever.
  • Ignition coil and muffler removed.
  • The saw is turned over and the engine is shut off by removing the housing screws.
  • The pan is unscrewed and the piston is removed.
  • Since the piston is only removed together with the crankshaft, it is necessary to remove the mounting rings in order to disconnect it.
  • The old piston is replaced with a new one, but as carefully as possible. This is due to the high fragility of the compression rings.
  • The sump is put back in place and sealant is used in place of the gasket.
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All subsequent steps are performed according to the reverse algorithm of disassembly.

Gasoline leaks from chainsaw

If there are occasional drops of gasoline on the body of the chainsaw, check the fuel tank for leaks. It may dry out over time. Or the gasket “goes numb” and can no longer perform its direct function.

compression, chainsaw

If there are full streams of gasoline, you may have to replace the burst hose connecting the carburetor and the fuel tank.

No gas getting into chainsaw cylinder

There are several reasons why the fuel mixture has stopped flowing into the cylinder:

  • Air filter is clogged.
  • The carburetor settings have taken off.
  • The carburetor diaphragm is no longer damaged.
  • The ducts that carry the gas are clogged.

The chain saw is not working

In this case you should start troubleshooting with the filter elements. Mostly due to reduced capacity of the air and gas filters, the idle speed starts to “float”.

If the filters are okay, it is necessary to check the components of the gas system, and make sure that there are no spontaneous changes in the carburetor settings.

Filter

“Rich” or “bad” fuel mixture will sooner or later lead to a breakdown. It may even be expensive. To prevent this, it will be a good idea to check the filter regularly for abrasion, as well as filter fabric breakage.

How to check and replace the fuel filter

To check the current condition of the fuel filter, follow these steps:

If the gasoline is flowing unevenly and irregularly, it’s time to put in a new filter element. This is done quite simply:

  • Fuel filler cap unscrewed.
  • Using tweezers or any other device, the filter itself is removed.
  • After disconnecting the old filter, you must install the new filter and lower it into the fuel tank.

How to Clean the Air Filter

If not enough air comes in, the fuel mixture becomes over-enriched, causing the engine to malfunction. Regular cleaning of the air filter and, in especially severe cases, washing in soapy water will prevent these problems.

compression, chainsaw

Note that flushing with acetone, gasoline, or other corrosive solutions is prohibited. This can damage the integrity of the filter element.

Unspecified category error

In some cases, chainsaw owners have to face more difficult challenges in order to fully restore the functionality of their cutting tool.

The chainsaw does not develop full power

In addition to the problems discussed above, a clogged muffler can be the cause of poor power due to a lack of gas or air entering the cylinder.

Decreased carburetor pressure and clogged nozzles

Over time, the screws securing the carburetor cap may become loose, or the gaskets may become unusable. A clogged filter or improper replacement can clog injectors. All of these factors also adversely affect chain saw performance and shorten the life of the tool.

Chainsaw loses power under load

If the saw loses power somewhere during operation, you should look for the problem in the following places:

Repair of chainsaws with their own hands: the fuel supply system

If the fuel mixture is not getting into the cylinder, but the spark plug is working fine, it could mean that:

To clean this assembly, you should remove the fuel hose and check the jet. If it is weak, the filter should be taken out through the fuel tank filler hole and cleaned or replaced if completely worn out.

As a preventive measure, it is recommended that the fuel filter be changed at least once every 3 months.

This is nothing but a hole in the fuel tank lid, which is cleaned with an awl.

There could be several reasons for this:

  • the air filter is clogged (in this case it must be removed, rinsed with water, dried and put back in place);
  • The carburetor settings have gone astray (which means this assembly needs to be readjusted);
  • The integrity of the carburetor membrane is compromised (must be replaced);
  • the carburetor ducts are clogged (you need to disassemble and clean all parts and components).

Running in of Chinese chain saws

Many users will say, well, when it comes to brands like STIHL, Echo, etc.д. can afford to have quality production processes. What about the cheap Chinese? The answer is yes, they may not have the best surface finish. Although you have to keep in mind that the same STIHL machines are also made in China, which doesn’t make them any worse. But often normal modes without extra torque (without the bar getting jammed in the barrel, which should be avoided at any other moment) are more useful than “fuel mixture enrichment” or, God forbid, idling.

A sprocket or centrifugal mechanism, a part that resembles a star in shape. It absorbs engine torque and transmits it to the guide bar and saw chain. This guarantees the rotation of the cutting attachment and the sawing process itself. It operates in automatic mode, which depends on the value of the engine speed.

The clutch drum can be located either on the outside of the chainsaw or on the inside of the chainsaw. under a separate cover. It has a protective function not only for the sprocket material, but also for the operator who can be injured by it while working. In addition to the chain rotation function, the drive sprocket prevents malfunctions in the engine system if the chain jams or stops turning.

The exception to the rule

The exception to the rule may be the running-in procedure performed when repairing the saw. When replacing pistons, rings, and other moving parts, it is up to the repairman to decide if this procedure is necessary. This may be due to the fact that parts that have never worked with each other before, with different surface cleanliness, and in addition, when replacing parts not performed those operations that are usually performed in the factory for the initial assembly.

However, even in this case, a competent technician will never leave the saw idling. It will be good practice to rotate the rotor with an external device in the presence of oil.

Faults of the Chinese chainsaw: an overview of popular and ways to solve them

Buy a cheap chainsaw made in China is not very difficult: the markets, construction hypermarkets and online stores offers a huge number of chain saws from the Celestial Empire. However, the low price almost always hides poor quality.

The most popular malfunctions of Chinese chainsaws should include:

  • Poor operation of the lubrication system. Clogged oil ducts are cleaned, and if the oil pump failed, it is necessary to replace it.
  • The starter rope tears.
  • Breakage of plastic starter shaft. An ordinary metal bolt will do for its replacement.

If you have the slightest suspicion that your chain saw is malfunctioning, it is worth carrying out a complete diagnosis right away. Only with proper use and timely maintenance can you expect a long service life from your chain saw.

Almost every villager or dacha owner has a chainsaw these days. They are in high demand, because they are quite easy to work with. Even if they break down, they can be repaired with their own hands, but it can be very time-consuming. On the farm, consumers use household or semi-professional (farm) saws that are designed for small jobs.

Compression in STIHL MS180 and POULAN 2250 chainsaws.

Compression in STIHL MS180 and POULAN 2250 chain saws.

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compression, chainsaw

Today we are going to measure the compression. To do this, we’re going to need. electric drill with reverse function and a maximum speed of about 2500-3000 rpm, a car compressor, a flexible shaft to transfer rotation from the drill to the chainsaw crankshaft

and, strictly speaking, the experimental samples and the Poulan 2250.

It’s worth noting that the STIHL. is a perfectly working saw (for repairs, which they replaced with a starter cord), but the Poulan with a deliberately ruined piston.

On both chain saws the carburetors are dismantled for accuracy of measurement (the intake resistance should be as small as possible), the starter caps are removed (to remove the flexible shaft with a “13” head on the nuts that fix the flywheels), the spark plugs and shutoff buttons are unscrewed in the “off” position

compression, chainsaw

Compression measurement on 2-stroke engines

measure the compression ratio how many bar(atm) the working engine should be.