The Druzhba chainsaw is designed for felling forests and sawing logs. Thanks to its convenient design, the technical characteristics of even models from the 60s remain acceptable for many consumers.
To keep the saw in working condition, preventive maintenance of all components must be carried out regularly, and adjustments must be carried out at least once a year.
Device
The main parts of the chainsaw are as follows:
- engine;
- sawing apparatus;
- frame with handles;
- gas tank
The engine is a single-cylinder two-stroke carburetor. Cooled by air flow created by a centrifugal fan. The engine and sawing apparatus are independent units, connected into 1 unit with flange fasteners and secured with a clamp.
When the fuel tap is opened, fuel enters the diaphragm carburetor, which ensures uninterrupted supply to the engine at any angle of inclination and strong vibration. The design of the chainsaw does not allow the engine to stop if the chain gets jammed in the barrel while cutting wood.
The handles are located high, which provides the following capabilities:
- do not bend over while working and get tired less;
- work in deep snow conditions;
- increase user safety.
Repair and operation instructions
It is not particularly different from the standard ones and has sections in its structure:
- specifications;
- restoration;
- preparation for work;
- starting and stopping the engine;
- running in a new chainsaw;
- Maintenance;
- storage;
- adjustment work;
- and others.
For those who need repair instructions, go to the Instructions section on our website and download it.
Characteristics
Over the 60 years of production, the design of the Druzhba chainsaw and its characteristics have changed insignificantly.
The general parameters are:
- weight when fully equipped - 12.5 kg;
- dimensions - 865x460x500 mm;
- saw bar length - 450 mm;
- The fuel tank capacity is designed for 1.5 liters of fuel liquid;
- spark plug - any with a diameter of 17 mm.
The main difference between the modifications is power. It is indicated by the number in horsepower at the end of the model names.
Friendship 2
The technical characteristics of this model are as follows:
- engine power - 2.2 kW;
- saw starting type - manual;
- lack of a rotary gearbox.
What makes Druzhba 2 different from the first model is the presence of a device for braking the chain, which made it safer: the tool cannot accidentally injure the worker or the people around him. The material from which the case is made is reliable and can withstand any temperature changes.
Friendship 4
This model received a gold medal at the World Technology Exhibition in Brussels in 1958.
The technical characteristics of the chainsaw are as follows:
- power - 2.94 kW;
- engine oil tank volume - 150 ml;
- total shaft rotation speed - 5000-5400 rpm;
A gas-powered saw can cut through a trunk with a diameter of up to 50 cm in 1 minute.
Friendship 4M electron
The Druzhba 4M electron chainsaw is distinguished by the fact that this model is equipped with an electronic non-contact ignition system, which significantly increases the reliability of the engine.
The technical characteristics of 4M are as follows:
- power - 3 kW;
- fuel consumption - 720 g/kW h;
- the distance between the spark plug electrodes is within 0.6-0.7 mm.
The inner walls of the aluminum cylinder liner are plated with chrome to increase wear resistance. The model is equipped with rubber shock absorbers that reduce the transmission of engine vibration to the handles. The Druzhba-4M model uses a KMP-100U carburetor, and with the Druzhba 4A modification, the use of forced chain lubrication began due to the installation of an oil pump. This made it possible to significantly increase the service life of the chain and guide bar.
Homemade products from “Friendship-4”
The layout of the engine and gearbox of this saw is so successful, and the clutch is so compact that the device is an almost ready-made power unit for many interesting homemade products.
In 1973, based on these engines, the MAI X-3 ultra-light helicopter was created, followed by modifications 4 and 5. They were even shown at a number of exhibitions, but did not go into mass production. It was too difficult to coordinate the operation of as many as 8 engines for 2 propellers that ensured its movement.
But he flew! But driving the engine from Druzhba is much easier. On snow and on hard roads.
True, sufficiently high speeds at the output gearbox of the saw require the installation of a large driven gear on the traction wheel, an intermediate reduction shaft, or a reduction in the diameter of the wheel itself.
But snowplows and motor cultivators from it turn out to be quite productive, but also with a system that reduces the speed.
Finally, it is worth remembering that the saw is equipped with a system with a hydraulic wedge.
This device is a great help when felling trees. How it works will become clear after watching the video:
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Advantages and disadvantages
The advantages of the Friendship saw are:
- long service life;
- simple device - you can quickly access any node without much difficulty;
- smooth and precise cutting;
- high performance;
- maneuverability;
- All parts are reliably protected by a durable casing.
The successful design of the Druzhba 4 chainsaw engine made it possible to use it in the production of walk-behind tractors, lawn mowers, and also to develop on its basis the SD-60 engine for driving stationary installations - generators, pumps.
The disadvantages of a chainsaw include the following:
- heavy weight;
- removable rope starter.
Modifications
During the entire production of the chainsaw, Friendship 4 has not undergone any major design changes. Let's see what minor changes have occurred in the design of the chainsaw:
- 1950 - 1960 . The first structural modification concerned a change in the mounting option for the handles; they began to be attached to the fan cover, and subsequently the fastening was moved to the clamp that connected the engine and gearbox.
- 1960 - 1980 . At this time, a modification of the chainsaw called Druzhba - 4A, which had two main advantages: a contact magneto and the well-known KMP-100 carburetor, entered the assembly line and was produced for 20 years. At the end of the 80s, the modification of the Druzhba -4A chainsaw was discontinued.
- Late 1980s. Release of the Druzhba-4M Electron modification. Electronic ignition was used for the first time.
- 1990s . Equipping the chainsaw with a modern (at that time) carburetor KMP-100U. Changes in the saw set - the use of modern type chains.
Many people are confused and say that a number of other changes were made to the Druzhba 4 chainsaw, such as a removable starter, a detachable crankcase and a removable cylinder, but they are deeply mistaken. All these changes were made on the Ural chainsaw, the basis of which was Druzhba.
Operation, maintenance and repair
To ensure trouble-free operation of the saw, it must be adjusted periodically. The operating instructions supplied with the equipment describe the features of setting up the model. Incorrect configuration will lead to unbalanced operation of the nodes.
How to adjust the carburetor
Failures occur when not enough or too much fuel is supplied, as well as if the proportions when mixing fuel with air are violated.
Carburetor adjustment is carried out as follows:
- The fuel regulating screw is first turned all the way, and then back (counterclockwise) 1.5-2 turns.
- Start the engine, warm it up for 1-2 minutes and turn the T screw in one direction or another to ensure its stable operation at maximum speed. The chain should not move along the bar at idle speed.
- Check and, if necessary, seal the connection between the carburetor and the cylinder.
It is easier to adjust the carburetor using a tachometer, but at home, in most cases, engine operation is adjusted by ear. When both the quantitative and qualitative fuel supply is normal, the engine does not overheat, does not choke, runs smoothly, without sharp sounds. When adjusting, turn the screws slowly, without jerking.
How to set the ignition
Stable operation of the engine is ensured by correctly adjusted ignition - the Druzhba 4 chainsaw in this case will consume a minimum amount of fuel. The saw is ignited thanks to a magneto using a spark plug and a special wire.
To monitor the quality of the spark for igniting the chainsaw, place the spark plug on the cylinder body and pull the starter. If the spark plug is in working condition, a spark will jump between the electrodes. A weak spark will not ignite the fuel; such a spark plug must be replaced.
It is better to replace the contact ignition of a chainsaw with an electronic one. This will eliminate constant problems with its regulation. It is necessary to ensure that the ignition coil mounting screws do not loosen.
Basic malfunctions and their elimination
If you know why the tool malfunctions, you can repair it yourself at home.
When the Druzhba 4 chainsaw engine starts and stalls, the reasons may be as follows:
- There is not enough fuel in the gas tank. It is necessary to add the mixture according to the instructions supplied with the instrument.
- The spark plug was splashed with fuel. This prevents a spark from forming. The candle must be removed, dried, and heated on a gas burner.
- Poor contact between spark plugs and wire. This occurs due to the increased gap (more than 0.5 mm) between the tip of the spark plug and the wire. The spark plugs must be cleaned of carbon deposits with a wire brush and blown with air. They need to be changed periodically.
If engine malfunctions occur at idle, repairing the Druzhba 4 chainsaw comes down to the following:
- replacing the fuel mixture with reducing the amount of oil;
- cleaning the air filter and muffler (due to its clogging, the engine runs but does not develop speed);
- checking the fuel line and replacing the tube if necessary.
If the cutting speed has decreased and the tire is “driving”, pay attention to the sharpness of the saw teeth. A well-sharpened chain is more important than a strong engine. It is best to take it to a master for sharpening or use a machine with a rotary sharpening disk. The bevel of the Friendship saw blade on the bottom edge is 45°, and on the side edge - 60°. The height of the limiting protrusions relative to the chain teeth should be the same and checked after 3-4 sharpenings of the chain.
It is recommended to place the chain in liquid lubricant for some time, preferably heated.
The reasons why the Friendship saw does not start may be the following:
- The fuel mixture does not comply with the repair and operating instructions for the model.
- Manufacturing defects. Repairs are carried out in a warranty workshop.
When assembling, even if the parts fit tightly, you should not use force, for example, hitting them with a hammer. By replacing worn elements, you can restore the functionality of the chainsaw or extend its life.
Chainsaw device
For quick maintenance and effective repair of the Druzhba 4 chainsaw, you should know its structure. You can read in detail about the device and design features in the operating instructions. In it you can also find tips and tricks for repairing and troubleshooting yourself. For visual reference, we recommend looking at the photo below; it shows all the main components, numbered and signed.
Please note that in the lower right corner there is a diagram of the carburetor, which consists of only 15 parts. In the upper right corner is a general diagram, and on the left side is a cross section of the Druzhba-4A Electron engine.
How much does a Druzhba chainsaw cost?
Chainsaw ZiD Druzhba 4 can be bought for 15 thousand rubles. The price of a used unit depends on its condition, the degree of wear of the main elements, the total service life, the presence or absence of all components, a passport and ranges from 1 to 7 thousand rubles. For example, a Druzhba-Altai chainsaw from the 90s, which differs from the basic one in an improved carburetor and saw system, can be purchased for 5 thousand rubles.
Spare parts are in demand. The most worn part - the sprocket - can be bought for 100-150 rubles, the starter - for 600-700 rubles, and the electronic ignition system - for 1 thousand rubles.
What to do with spare parts
You won’t find spare parts for the Druzhba 4 chainsaw in stores; after all, it’s already a rarity. The only place where you can still buy them is at a flea market - a market where grandparents sell what they have lying around at home. Believe it or not, you can find many spare parts there in new condition. They lay there for a long time, but were never put on the saw.
Another place is bulletin boards, like Avito. They especially often sell chains and tires for Druzhba chainsaws.
Carburetor adjustment and muffler cleaning
If excess fuel is eliminated, but the breakdown is not corrected, then the carburetor may not be adjusted.
To fix this, follow these steps in strict order:
- turn the fuel screw until it stops;
- unscrew it three turns. No more, no less;
- screw the propeller firmly;
- unscrew it already two strict turns;
- Seal with sealant or wrap thin sheet metal around the adapter coupling.
Everything that must be firmly and tightly connected. The quality of the chainsaw depends on this.
There are times when the chainsaw motor only works at low speeds and stalls at high loads. A similar problem may indicate a clogged muffler.
The muffler spark arrester can become clogged for several reasons:
- Using low-quality oil;
- The fuel mixture has a high oil level;
- Using oil not intended for such engines.
In any of these cases, you need to remove the muffler and clean it well with various detergents. After that, dry it with a hairdryer.
Read here how to choose the right chainsaw.
The Druzhba chainsaw is a mechanized tool that is used to cut thick branches, clearing power line routes, as well as felling trees. Whether a given instrument is of the highest quality or not is difficult to answer. Some consider him a reliable assistant, while others do not like him, as he is clumsy and capricious. Nowadays, this chainsaw model is popular not only in Russian markets, but also outside the Russian Federation. This unit is available in almost every family living in villages and villages. Therefore, whether it is reliable or inconvenient is impossible to answer. But like any other tool, this chainsaw tends to break. Is it possible to repair a Druzhba chainsaw yourself at home? If you wish, you can. But, if it is carried out in specialized workshops, then this repair will result in a good amount.
What can be done to extend the life of a chainsaw without repairs?
Repair of the crankshaft main bearing has to be carried out quite often, since this is the most vulnerable point of this model of chainsaw. As soon as it becomes faulty, the ignition begins to go astray, which leads to unpredictable operation of the tool. With such a breakdown, in some cases it is almost impossible to start the chainsaw. But in other cases it simply cannot be drowned out in any way. This model was recently equipped with a button that forcibly stops the operation of the unit. Craftsmen who are well versed in this have installed such buttons on their units themselves much earlier. Chainsaw Friendship is a capricious tool. Under intense load, it has a considerable list of failures, including broken connecting rod, jamming of the piston, as well as loss of spark and gearbox malfunction.
The presence of contact ignition in a chainsaw also causes a lot of trouble, since it is sensitive to various brands of not only oil, but also gasoline. Therefore, to prevent this problem from leading to tool repair, experts strongly recommend replacing the contact ignition with an electronic one. This model of chainsaw should be constantly adjusted and tuned. If problems with the carburetor are quite common, then you can solve it by bending the gasoline valve inside. As a result, the amount of fuel that enters the engine is limited.
How to adjust the carburetor on a Druzhba-4 chainsaw
Adjusting the carburetor of the Druzhba-4 chainsaw is required when the engine starts to work incorrectly - it stalls at idle, does not pick up speed when gas is applied, and “fails.”
To access the adjusting screws of the KMP-100 carburetor, you do not need to remove the housing cover; they are always open and accessible. There are no screw markings on the carburetor body, like on modern chainsaws. The first screw, which is located closer to the cylinder, regulates the fuel supply at low and medium speeds. The second screw is the main screw, it regulates the fuel supply at maximum speed
Required Tools
A screwdriver (minus) is required for operation. If desired, you can use an electronic tachometer. It will show the number of revolutions before and after adjustment.
General adjustment algorithm
The carburetor is adjusted in different ways. The simplest and most effective is ongoing adjustment during operation.
Lots of gasoline - spin
- The engine is warmed up for 5-10 minutes.
- If in the “full throttle” mode the engine operates as if idling (does not develop speed due to excess gasoline in the fuel-air mixture), the second (farthest from the cylinder) screw is tightened clockwise 1/4 turn.
- If the engine begins to work better, tighten it another 1/4 turn. If the engine starts to stall when the gas is fully applied, the screw is unscrewed back.
Low on gasoline - unscrew
- If the engine stalls in the “full throttle” mode (there is not enough gasoline in the fuel-air mixture), the adjustment begins by unscrewing the second screw by 1/4 turn and testing the operation of the engine. If it gets better, unscrew it some more until the engine begins to “choke” and run as if idling at full throttle. Then the screw is tightened back.
After adjusting the second screw, check how the engine operates in the transition from idle to medium and maximum speed. If there are dips, unscrew the first screw 1/4 turn and test changes in engine operation.
As a result, the optimal operating mode of the engine is found through such trial regulation.
Adjusting the idle speed on the Druzhba-4 chainsaw is done using a screw located on the gas handle. Its position determines how far the throttle valve in the carburetor is open at idle.
Idle speed is adjusted based on two requirements:
- The engine should not stall.
- The chain should not spin.
Adjustment in a different sequence is possible. The screws are first tightened to the end, then unscrewed by 0.5 - 3 turns (different sources indicate different numbers of turns).
The video shows a simple and understandable process for adjusting the KMP-100 carburetor on the Druzhba-4 chainsaw from the screws position “tightened completely and then turned out”:
For beginners, we recommend watching a more detailed video about adjusting the KMP-100U carburetor of the Druzhba-4 chainsaw. The author of the video tells everything that is useful and everything you need to know. Just a whole step-by-step guide from A to Z.
Step-by-step algorithm
- Unscrew the fastening screw.
- Remove the fuel hose.
- Unscrew the top damper cover.
- We remove the carburetor.
- Remove the membrane cover to adjust the level. You need to unscrew 6 screws in a circle.
- Let's half the body and assess the condition of the membrane, it must be intact - this is the main thing, cracks, scuffs, and tears are not allowed.
- We evaluate the performance of the mechanism responsible for the operation of the valve.
- We blow through all the holes and clear out any debris if there is any.
- We set the level by adjusting the height of the tongue; it should be on the same edge as the body.
- If everything is done correctly, then by applying, for example, a ruler, you will see that the tongue and the edges of the body are on the same level.
- We unscrew the screw with the needle from the central jet and assess its condition, clean everything from dirt, if there is any, blow it out in any case. The screw located above, also visible in the photo, is responsible for idle speed; it also needs to be unscrewed, the condition assessed and blown out with air.
- This completes the cleaning, put everything back together in the reverse order and put the carburetor back on the chainsaw.
- Don't forget to replace the air filter and pump up the fuel before starting.
- Let's try to start the chainsaw.
Possible nuances and problems
In any case, when tightening the screws all the way, you need to remember the number of turns made for each screw. This will make it possible to return to the original adjustment if suddenly the chainsaw, adjusted according to the recommendations, does not start at all.
The problem is also that Druzhba-4 chainsaws of late production may have different carburetors, completely different in design from the KMP-100. For example, with one adjustment screw or no adjustment options at all.
Ignition system repair
Childhood chainsaw disease Friendship 4 - difficulty starting a hot engine when stopped in operation. The reason for this is a weak and outdated ignition system. To increase the power of the spark at the plug, it is necessary to repair the ignition. Such a repair will correct the situation even if there is no standard coil.
Step-by-step algorithm for repairing the ignition of petrol tools Druzhba 4
- The high and low voltage windings are removed from the standard ignition coil.
- Instead of a low-voltage winding, 250 turns are wound onto our coil with special wire (for transformers). You can use PEV2 wire, with a cross section of 0.8-1 mm. We must not forget about interlayer insulation - a new layer of special wires is laid with paper. The beginning of the entire winding is connected by soldering to a standard output to the magnetic core, the other end of the winding is connected with a special mounting wire to the breaker. Then the coil is wrapped with electrical tape or covered with another insulator. The section of the capacitor circuit fed to the coil and the breaker does not undergo changes.
- Using two wires through a piece of insulating tube, the ends of the connections are made. To prevent short circuits, all the resulting wiring can be placed in one insulating tube.
- An ignition coil of type B-115 with a removed side resistor is ideal as a transformer. This type of coil is used in ignition of old Soviet Muscovites. It is not recommended to use motorcycle ignitions; they are not powerful enough to provide the required spark. The reel can be fixed to the chainsaw frame using a mounting clamp in any suitable place.
- The wires from the internal combustion engine are switched according to the following scheme: the first wire, which connects the breaker, capacitor and coil output together, is connected to terminal B-115 with the designation “VK”, the second wire, which comes from ground, connected to the magneto mounting screw, is connected with output B-115 without identification marks. To make the diagram easier to read, it is better to use different colored wires.
- Finally, the ignition coil is connected to the engine spark plug igniter using a high-voltage wire.
This repair of the ignition system showed an excellent result, the childhood disease of the Druzhba 4 chainsaw disappeared, such a system will work for a very long time.
The only drawback is that the appearance of the chainsaw has changed due to the external coil on the body, and the dimensions have increased. But this is a forced alteration, but the ignition system works reliably and the saw starts at any temperature.
If some points remain unclear, we suggest watching a video on the topic of repairing the ignition of the Druzhba chainsaw.
