Chainsaw patriot 3818 DIY repair

In detail: the patriot 3818 chainsaw do-it-yourself repair from a real master for the site my.housecope.com.

The chainsaw is a worthy replacement for hand saws and axes. Today, this tool is available in almost every household - it is indispensable for setting up a personal plot, construction and repair work. Intensive use and improper care of the tool can lead to premature failure. However, the owner of the chainsaw does not have to go to the workshop right away - many of the faults that can happen to her during operation are quite realistic to eliminate on their own.

Correct diagnosis is essential for a successful repair. Therefore, in order to determine why the chainsaw failed and, most importantly, how to make it work again, you first need to know the features of its design.

It should be noted that it does not differ in particular complexity, since it includes:

engine (two-stroke gasoline);
functional part (saw bar and chain);
systems that ensure the joint operation of these two units (ignition, filtration, lubrication, etc.), that is, the tool as a whole.

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

engine malfunctions;
malfunctions of other parts of the chainsaw.

Most often, failures occur in the engine systems, however, the rest of the tool, due to intensive use or improper care, can fail at any time. How to determine exactly where the breakdown occurred? Simple logic will help us with this.

If the problem is in the engine, it will:

Video (click to play).

do not start;
deafen;
work unstable;
overheat;
smoke;
develop insufficient power.

As for all other malfunctions, as a rule, they manifest themselves with a normally operating motor.

If your chainsaw won't start, the first thing to do is to check for a mixture of fuel in the tank. By the way, it must be prepared in the proportions indicated by the engine manufacturer, otherwise the instrument will simply not start.

After verifying that the fuel mixture is correct and available, the ignition system should be checked. To do this, you need to inspect the spark plug.

Her condition can say a lot:

indicates that the fuel mixture does not enter the carburetor, which means that the problem is not in the ignition;

is the result of an overabundance of the fuel mixture, which lies either in a violation of the engine starting algorithm or in an incorrect carburetor adjustment;

this is a signal about the presence of low-quality oil in the engine lubrication system, incorrect carburetor settings, or an incorrectly prepared fuel mixture.

If the spark plug is splashed with fuel, wipe it thoroughly after removing it. The fuel supply system should also be cleaned. To do this, it overlaps, after which the starter is turned on. A carbonized candle must be carefully cleaned with an awl and emery.

When checking the spark plugs, you should pay attention to the distance between the electrodes (the normal gap is 0.5-0.65 mm), as well as the condition of the gasket and the presence of a spark. A damaged or worn gasket will have to be replaced, and the spark can be checked by putting on the ignition cable, connecting the cylinder and plug nut, and starting the starter.

If the discharge does not occur, the plug must be replaced. In the event that a spark does not appear with a new candle, then the problem is in the connection to the high-voltage wire or in it itself.

If the fuel mixture does not flow into the cylinder, but the spark plug is working properly, this may mean that:

Clogged fuel filter.

To clean this unit, remove the fuel hose and check the jet. If it is weak, the filter must be removed through the filler hole of the fuel tank and cleaned or replaced if completely worn out.

As a preventive measure, it is recommended to replace the fuel filter at least once every 3 months.

This is nothing more than a hole in the fuel tank cap, which is cleaned out with an awl.

The fuel mixture is not supplied or is supplied insufficiently.

There may be several reasons for this:

the air filter is clogged (in this case, it must be removed, rinsed with water, dried and replaced);
the carburetor settings are out of order (which means this unit needs to be re-adjusted);
the integrity of the carburetor membrane is broken (must be replaced);
the channels of the carburetor are clogged (it must be disassembled and all parts and assemblies must be cleaned).

If at low speeds the engine of the chainsaw works normally, but at high speeds it starts to stall and smoke, the problem may be hidden in the muffler.

To check the quality of its work, you should do:

dismantling (with the obligatory closing of the outlet);
disassembly (if the muffler is collapsible);
cleaning from carbon deposits using special detergents or dry method;
drying (using a hair dryer);
reassembly and assembly.

Dry cleaning without respiratory protection is not recommended. The carcinogens present in the soot will be released into the surrounding atmosphere in the form of dust, the inhalation of which is extremely hazardous to health.

To prevent clogging of the muffler during the operation of the chainsaw, you should carefully monitor the composition of the fuel mixture and the quality of its components.

If the chainsaw engine does not start or cannot develop normal power, it is likely that sufficient pressure does not build up in the engine cylinder for combustion of the fuel mixture. The reason for this may be the wear of the elements of the cylinder-piston group - the piston, rings, bearings, etc. In order to assess the condition of this unit, it should be visually inspected, having previously removed the muffler.

For a more complete diagnosis, a compression gauge is placed in the spark plug hole of the two-stroke engine of the chainsaw. It measures the compression in the engine. Based on the results of the check, one can judge the state of the CPG, however, the exact facts can only be obtained with a complete disassembly of the unit.

If the piston is chipped or scratched, it will obviously need to be replaced. The same applies to deformed or broken piston rings - for normal engine operation, they must be completely intact and free of carbon deposits.

A properly working carburetor guarantees maximum efficiency of the chainsaw, that is, it is possible to develop full power with the most economical consumption of the fuel mixture. The adjustment of this unit is usually carried out by the manufacturer, but its design provides for the possibility of adjustment already during operation.

The fact that such a setting will have to be performed by the owner of the chainsaw is evidenced by:

Strong vibrations or damage to the protective cover.
CPG wear.
Carburetor clogged.
Inability to start the engine or its spontaneous stops after starting.
Increase in fuel consumption and emissions while decreasing engine power.

Chainsaw carburetor adjustment is carried out in strict accordance with the manufacturer's instructions using three special screws, which are responsible for the maximum ("M") and minimum ("L") revolutions, as well as the idle speed of the engine ("T"). In order to exclude unwanted interference by an inexperienced user with the carburetor operation, some manufacturers install only one idle screw.

Carburetor adjustment is carried out in two stages:

Basic (carried out with the engine off).
Finishing (carried out with a running, pre-warmed engine).

For basic adjustment, screw in screws H and L as far as the stop and back out 1.5 turns. Final adjustments require the engine to warm up for 5-10 minutes at low revs.

The final calibration is performed by unscrewing the idle screw until the minimum engine speed is reached (in this case, its operation must be stable, and the chain must be stationary). If the engine stops at idle speed, the screw must be returned back, and if the saw chain is still in motion, continue turning counterclockwise.

Calibration check is performed by test:

Acceleration (with a smooth press on the accelerator, the engine should quickly pick up speed to the maximum indicator).
Maximum speed (if there is an ignition interruption, screw H should be slightly loosened).
Work at idle speed (the chain should not move, and the engine should pick up speed as quickly as possible).

If the owner of the chainsaw is not familiar with the carburetor device and does not have the tool necessary to calibrate it, contact a specialist. The carburetor is a very complex unit, so any wrong action can lead to irreversible consequences, for example, complete engine failure.

If the diagnostics showed that everything is in order with the engine and its systems, then the cause of the malfunction should be looked for in other units of the chainsaw. The most common problems are:

failure of the starter;
improper operation of the lubrication system;
incorrect operation of the chain brake;
saw chain wear, etc.

If the cause of the tool failure is not visible to the naked eye, as is the case with the engine, it is necessary to perform a thorough diagnosis of the faults and eliminate them in accordance with the manufacturer's recommendations and safety regulations.

The low level of technical equipment of many service departments and the high cost of their services, forcing many owners of faulty chainsaw equipment to repair their gadgets on their own. How to disassemble a chainsaw, replace faulty parts, and also correctly assemble a chainsaw with a minimum investment of time and money?

Self-disassembly of a chainsaw presupposes the availability of spare parts, appropriate tools and locksmith skills. It is possible that for the dismantling of individual parts, special pullers will be required, the manufacture of which will take more time than the repair itself.

In a number of modern models of household and semi-professional chainsaws, special keys not included in the supplied set are used to adjust the carburetor and dismantle the saw chain drive sprocket.

The problem in many cases is aggravated by the lack of complete information on the repair technology. According to foreign manufacturers, after the resource has expired, the saw should be scrapped, therefore, the maintainability of many budget-level models raises reasonable doubts.

It is more difficult to restore professional-grade chainsaws.

The problem is compounded by the high cost of spare parts.
It is possible that in order to restore the performance of individual units and mechanisms, in particular, to adjust the fuel equipment, special equipment will be required.

Replacing expensive branded parts with affordable, but short-lived Chinese counterparts does not justify itself economically. Practice shows that these components develop a resource by 50-60% at best.

Saw failure or poor performance can be caused by:

clogged fuel tank cap breather;
air leaks by the carburetor due to the destruction of the gasket or the weakening of the threaded fasteners;
mechanical seizure of removable saw equipment and other minor defects.

Before starting disassembly, make sure that more extensive repairs are necessary.

It is most likely that it will not be possible to assemble a new chainsaw on your own after repair with the original quality. In the design of modern chainsaws, press fits of mating parts are often used, which have minimal maintainability.

Even a partial disassembly of a chainsaw with the help of an improvised tool can lead to undesirable consequences. In most cases, to troubleshoot a malfunction, you can limit yourself to dismantling a separate unit or system.

This list includes:

connecting rod and piston group;
carburetor;
clutch mechanism;
saw chain sprocket.

Within the scope of this article, only general recommendations can be given, since chainsaws from different manufacturers can 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.Dismantling the carburetor requires special attention. This assembly consists of many small parts, so the removed parts are stacked in a predetermined sequence on a blank sheet of paper. After flushing all the components, the carburetor is assembled in the reverse order.Less complicated repair of the piston group. To dismantle the cylinder, it is enough to remove the threaded fasteners, lay the saw on its side to prevent pieces of the destroyed compression ring, piston skirt or other foreign objects from getting into the engine crankcase.The cylinder bore does not wear out evenly, so the installation of a new piston does not give a significant effect. As a rule, during a major overhaul, after checking the suitability of the crankshaft, a complete set is installed, consisting of a cylinder, a piston of a compression ring and a piston pin.Dismantling the starter to replace the cord does not create problems for an experienced user, but the plastic case in most cases cannot be repaired. Most of the Chinese chainsaw range is copies of the most popular European models, so we disassemble the Chinese chainsaw according to the standard scheme.Worn parts of the saw headset are not restored.

At home, you can shorten the new chain to fit a shorter bar.

The service life of branded tire accessories is equal to that of three saw chains.

This indicator can be significantly reduced by the wrong choice of the chain pitch or large wear of the rim of the drive sprocket.

You need to have a very small set of tools for this:

a set of keys (including a special key for spark plugs);
a diagram of the chainsaw device (usually it is included in the delivery set).

You also cannot do without elementary knowledge from the physics course.Add to that the ability to reason logically and you are almost ready to fix your chainsaw.

We will begin the repair with the "diagnosis" - the definition of the malfunction. First you need to unscrew the candle and inspect it carefully. Possible problems are listed below.

Types of spark plugs for chainsaws.

The candle is damp. We make a logical conclusion that the fuel mixture inside the combustion chamber does not ignite. The second reason can be water trapped in the cylinder. In any case, you need to dry the candle, blow out the cylinder. We do the same as when starting the chainsaw. The only difference is that the fuel supply valve must be closed and the throttle valve must be fully open. After that, we put on a cradle from the wire on the candle and check for the presence of a spark by pressing the candle against the cylinder body and trying to start the engine. If the spark is good, the reason may be the fuel - it needs to be replaced. If the spark does not appear or appears unevenly, then the cause of the malfunction should be sought in the ignition system. There may be a breakdown in the high-voltage wire or damage to the spark plug itself. It is enough to try using a spare plug to make sure that the first plug can still be used. If the spare plug does not respond to the start-up test, then the ignition system should be examined more thoroughly.

The candle is dry, but heavily soot-coated. This fact indicates that the balance between fuel and oil is imbalanced (there is too much oil!) Or one of the filters is clogged (fuel or air). Clogged filters first leads to a loss of power of the chainsaw, and then to its complete stop. Dust that gets inside the cylinder cannot be completely burned and settles on the inside of the cylinder in the form of a dense layer of soot.

Chainsaw fuel system: 1 - fuel filter, 2 - carburetor, 3 - manual pre-priming pump.

This drawback is eliminated as follows: the fuel is replaced, the fuel filter is cleaned (according to the instructions), the air filter is washed and dried. The candle itself is mechanically cleaned of soot using an awl, its contacts are cleaned with fine sandpaper.

The candle is dry and clean. Apparently, no fuel enters the cylinder at all. The cause may be either a clogged conductive tube or a problem with the carburetor. It is necessary to clean the fuel line of the chainsaw and check the operation of the fuel pump and carburetor. Repairing the named chainsaw units at home is almost impossible, so they are simply replaced.

Regarding the carburetor of the chainsaw, several important points still need to be clarified: manufacturers minimize the possibility of adjusting it, leaving access only to adjusting the idle speed. But even such a small amount makes it possible to achieve maximum power from the chainsaw.

By adjusting the idle speed correctly, you will notice that the engine runs more reliably.

But it is better to entrust the repair of the carburetor to the service specialists, since it can be done independently only if you have a lot of experience and certain knowledge.

Chainsaw two-stroke engine diagram.

We will assume that you were able to do everything accurately and your chainsaw began to show signs of life, but there are problems with power. It happens very often that the engine works well at idle, but the chain speed increases very slowly when the accelerator lever is pressed, or the chainsaw simply stalls. The problem may be that the exhaust gas outlet is clogged. It is not difficult to eliminate this deficiency.

First you need to unscrew the muffler. The piston must be set to the uppermost position so that it blocks the channel and excludes the possibility of soot getting into the cylinder. And now the soot must be carefully scraped off the walls.You can use both a screwdriver and a thin chisel for these purposes. When cleaning, we try not to make great efforts, as you can easily mechanically damage the cylinder or piston. After removing the plaque, we wipe the cleaned surface with diesel fuel or gasoline, and the muffler can already be screwed on. Before this, the non-separable muffler should be washed with diesel fuel or low-octane gasoline and dried. Removing the soot will increase the power.

It is possible that none of the described home repair methods led to the desired result and the chainsaw still does not work. Most likely, you have a malfunction in the ignition system. It turns out that both the fuel comes in, and the spark on the spark plug is excellent, and the engine refuses to work.

We check the quality of the ignition control as follows: we turn off the spark plug, adjust the gap between the contacts (according to the technical data sheet of the product), connect it to the wire and press it against the cylinder body. And now we observe the moment the spark appears: it should appear at the extreme upper position of the piston. Visually it is noticeable. If deviations exist, then you need to adjust the ignition. It is produced in different ways for different chainsaws, but in general this process resembles ignition adjustment in other two-stroke engines.Repairing a chainsaw on your own is also permissible in case of problems with the chain brake. It usually happens due to surface contamination with sawdust or lubricants. The wear of the braking band itself is also possible. Simply unscrew the side panel and clean. If necessary, the tape is replaced. Image - Chainsaw patriot 3818 DIY repair

Chainsaw electronic ignition circuit.

Repairing a chainsaw that has problems with the cylinder-piston part involves disassembling the motor and replacing worn parts. This is the most difficult repair, but also the rarest. In modern chainsaws, breakdowns of parts of this group are rare. And this usually happens due to the marriage of the components of the mechanism at the initial stage of operation. During this period, you have the opportunity to get a chainsaw repair under a warranty card, so there is no need to make it yourself.

It should be noted that the main reasons that lead to the breakdown of chainsaws and their subsequent repair include violations of the operating rules provided by the manufacturer. First of all, this is a violation of the ratio of oil and gasoline in the fuel mixture. Very often, users of chainsaws do not even suspect that the prepared fuel mixture loses its properties under the influence of direct sunlight. The fuel changes not only its color but also its lubricating properties. Certain particles do become technically harmful additives that can disrupt the operation of the fuel system of a chainsaw. Hence, the conclusion suggests itself that elementary adherence to maintenance rules will allow extending the trouble-free service life of almost all chainsaws.

A few words must be said about other rules that will avoid repairs for the longest possible period. First of all, you need to have several buses (at least two) and several chains (at least 4) available. The tire should be turned 180 ° after every 3 hours of operation. After another three hours, we also replace the chain. This approach will allow uniform wear of all parts of the saw, which will eliminate distortions and additional stress.

It is constantly necessary to monitor the cleanliness of the entire mechanism and various openings. Clogged holes can cause the vacuum plug to prevent fuel or oil from reaching the required parts freely, causing the chain saw to stop.You should start repairing chainsaws at home only when you have certain skills in carrying out such repairs. Otherwise, such work should be entrusted to the specialists of the company service.Their experience will allow you to quickly diagnose a chainsaw and repair it with high quality.Chainsaws are available on the farm almost every resident of the village and many owners of summer cottages. They are easy to use and can be repaired by hand. Finding out the reason why the device does not start, troit, has problems with idling is not so difficult. Despite the types of chainsaws, the repair principles are the same.Chainsaws are divided by class and purpose.The purpose of the tool affects power, weight and dimensions. Chainsaws have three purposes:Before you start disassembling and repairing your chainsaw, prepare the necessary tools and accessories:

Overalls.

Gloves.

Free space on the table.

Candle wrench with screwdriver.

Chainsaw problems can be of two types:

Malfunctions of the engine, ignition system, fuel supply and exhaust.

Malfunctions of other components.

The following indicators will indicate that an engine diagnosis is required:

The tool will not start or will start and stall.

It is unstable.

It works at idle, and under load, the speed drops or stalls.

Lubrication system problems.

The chain brake does not work.

Broken or worn out chain.

The asterisk was worn out.

The appearance of the spark plug should be checked. Take the CANDLE KEY. Remove the insulating cap with the power cable. Unscrew the candle with the key. Fuel does not flow for three reasons:

There is a hole in the fuel filler cap that could be clogged. If this happens, a vacuum has formed, which prevents the fuel from flowing out.

A fuel filter is installed in the tank. It gets dirty over time.

Fuel is poorly supplied from the carburetor to the cylinder.

The first two reasons are identified in the same way. To do this, you must disconnect the hose through which the fuel flows from the carburetor. And check with what pressure it flows. If there is little or no leakage at all, then the tank cap is cleaned with a needle, and the fuel filter is replaced. But first you need to drain the combustible mixture and remove the filter from the tank with a wire hook. If fuel flows well from the disconnected hose, then the air filter is clogged or the carburetor is faulty. The air filter affects the flow of air into the carburetor and enrichment of the combustible mixture. When it is clogged, the mixture is too rich, as air does not come in. This affects the correct functioning of the engine.

Remove the air filter carefully to prevent dust from scattering. Cover the opening in the combustion chamber with a clean cloth.

Blow out the filter and clean with a soft brush. If the filter does not clean, rinse it. Put back after drying.

Before adjusting the carburetor, check that the air filter is clean and that the chain is tight enough. Read the instructions. The manufacturer describes how to properly adjust the carburetor. If there is no instruction, locate the three labeled screws:

H - screw for maximum speed.

L - minimum speed screw.

S - screw for fine adjustment of idle speed.

Take a screwdriver to adjust the carburetor and get started.

Basic adjustment. Produced with the engine off and cold. Turn screws H and L all the way to the right, that is, clockwise. Then one and a half turn to the left.

Idle speed adjustment. Before starting it, turn on and warm up the engine. Turning screw S to the right increases the speed, and to the left decreases it. You need to slow down and control so that the engine runs stably, without pauses. Make sure the chain is still. If the engine suddenly stops, increase the speed a little. And when moving the chain, decrease it.

Checking the engine for acceleration. Smoothly press the fuel button. The adjusted engine should quickly and confidently pick up speed to the maximum. If the engine is lagging and runs unsteadily, turn the screw L to the left no more than an eighth of a turn.

Adjustment of maximum speed. Ignition interruptions occur when maximum rpm is reached. Turn screw H slowly to the left until stability is achieved.

After all adjustments, check that the engine is idling. It should work stably with the chain stationary. If you do not achieve the desired result, repeat all adjustments, excluding the basic one.

When the muffler is clogged, the exhaust gases have nowhere to go. The saw will not run and will not start. The design of the chainsaw allows you to quickly remove the muffler. You may need an Allen key or socket wrench, depending on the mounting method. Unscrew the screws. Swinging the muffler slightly, remove it from the studs. Plug the hole in the engine with a clean cloth. The muffler is dirty due to poor quality oil or improper fuel mixture.