Chainsaw ignition installation friendship 4

The design and principle of operation of the ignition system on a Druzhba chainsaw

For more than 30 years, until the end of the 1980s, Druzhba chainsaws were produced with contact ignition (mechanical breaker). The principle of generating electricity is the same as that of more modern electronic systems. A magnetic rotor mounted on the crankshaft rotates inside the coils. The primary winding of the coil consists of several turns of thick copper wire and produces a current of low voltage (V, Volt), but quite high strength (A, Ampere).

The secondary winding consists of many turns of thin wire. In some ways it is a step-up transformer. Passing through it, the electric charge changes its characteristics. And the output voltage is 15-30,000 V at a scanty current (milliamps). This current is capable of producing a high-temperature spark (arc) between the electrodes across the gap, which can be observed on each spark plug.

The latest modification of this chainsaw with contact ignition, Druzhba 4A, was produced until the end of the 1980s. Afterwards it was replaced with Druzhba 4A Electron with contactless ignition, as indicated by the prefix in the model name.

Ignition of the chainsaw. Device, circuits, malfunctions.

The ignition system of a chainsaw is a whole complex of elements with the help of which a spark appears when the engine starts. It is needed in order to ignite the fuel and bring the engine into a state of full long-term operation. The main element of the ignition system is the spark plug, which must be ignited whenever the engine is in the desired operating cycle. And although the system is reliable and well thought out, sometimes it requires repair, so the user needs to know how his chainsaw works, as well as what he can do to repair its ignition system.

How does a chainsaw ignition work?

The design of the ignition system of modern chainsaws

Magneto Stihl MS 180

Previously, ignition systems were quite unreliable, but they have now improved. So, in their control system there are elements that regulate the impulse depending on the speed of the saw. Due to this, the engine runs more efficiently, which increases the overall efficiency of the tool. In addition, such elements are important because they make it easier to start the saw initially.

An equally important fact is the reliability of modern systems. If earlier the ignition failed very often, now all its components are so durable and high quality that they rarely need repairs.

So, a modern chainsaw ignition system consists of a flywheel magneto, a spark plug, a wire and an ignition switch. There are contact and non-contact magnetos. The device of the first is quite simple: permanent magnets (installed in the flywheel rim), an ignition coil, a capacitor and a breaker. The coil, in turn, includes the core, as well as the primary and secondary windings of the transformer. Another important element is the spark plug. Its design is as follows: central and side electrodes, insulator, outer casing.

How to check the ignition of Friendship

If the internal combustion engine of a chainsaw fails, in addition to the fuel supply, first of all check for the presence of a spark on the spark plug:

Remove the cap and unscrew the spark plug.
The spark plug thread is shorted to ground (cylinder ribs), and the starter is pulled. Contact ignition produces a large blue spark. Electronic - small yellow, difficult to see in sunlight. But this is the norm for electronic systems.
If there is no spark, replace the spark plug with a guaranteed good one and check again.
If the problem is not in the spark plug, remove the cap from the spark plug wire and, when the starter jerks, check for the presence of a spark between the bare wire and the ground with a gap between them of 0.2-1 mm.
If there is no spark at the output, check or change the spark plug wire.

DIY repair

When the above measures do not eliminate the problem, the reasons may be as follows. The electronic ignition unit has failed. All elements of this unit are sealed (filled with compound) and cannot be repaired. The entire unit needs to be replaced.

The cam (contact) ignition system of the Druzhba chainsaw is repairable. There are several reasons for its failure:

The textolite insulator of the moving contact of the breaker was pierced to ground. Replaces with a working one without any options.
The moving and fixed contacts of the breaker (cams) were burnt. Clean with a fine file or emery until the surfaces are smoothly adjacent to each other. They change when completely burned out.
The capacitor is designed to protect contacts from burnout. It rarely fails and does not directly affect the formation of a spark. When diagnosing, it is simply ignored.
Interturn short circuit, break in the secondary high-voltage turns of a coil with a thin wire.

Repair instructions for the Druzhba-4 carburetor

The most common causes of failure of the KMP-100 carburetor:

Contamination of fuel and air channels, nozzle holes.
Loss of tightness.
Failure of the membrane - rupture, loss of elasticity, etc.

In the first case, the carburetor is disassembled. The parts are laid out on a clean cloth, remembering which one comes from where. The body and parts are washed in gasoline. The channels and holes of the jets are purged and washed.

The tightness is restored by disassembling the carburetor, changing the gaskets or using a gas-resistant sealant.

If the membrane fails, it is replaced with a new one.

The Druzhba-4 chainsaw has a tank located on the handles and has a faucet with a filter, which can become clogged. You need to remove the fuel hose from the carburetor fitting and make sure that gasoline flows fully.

This carburetor can no longer be repaired. better to replace with a new one

Why does it overflow

If there is too much fuel in the combustion chamber, the spark plug may be flooded, the spark will disappear and the engine will not start.

If the engine does start, the engine cannot develop speed because there is not enough oxygen to burn the fuel.

If the overflow is small and the engine is running, there will be excess fuel consumption.

The second reason is the failure of the membrane and the valve associated with it. A broken membrane and valve do not regulate the flow of fuel, and it comes in excess.

A one-time overflow when starting a cold engine can be caused by excessive pumping of fuel by the enrichment button (choke or primer button).

How to adjust the ignition on Druzhba

The spark on the candle must flash strictly at a certain moment. On Druzhba - when the piston with a portion of the fuel-air mixture approaches the spark plug, not reaching 4 mm from TDC. Only with a precisely adjusted spark point will the engine operate normally. Deviations are called early or late ignition.

With small deviations in one direction or another, the engine will perform worse (lack of power, overheating, excessive fuel consumption, poor starting). With more significant ones it will not work at all. Can shoot into the exhaust system or carburetor.

Mechanical chainsaw breaker Friendship is simply regulated.

Before adjusting, you need to check - perhaps the fastening of the entire system platform has become loose and it has turned. It is checked by matching the factory marks (marks) on the metal base of the ignition and the engine crankcase. As a rule, they are stamped in the form of stripes on the upper right side of the ignition and should match. If there is a bias, it is corrected.

The maximum gap (at the peak of the divergence) between the cams (contacts) should be from 0.2 to 0.4 mm. Ideally 0.3 mm. Checked with a calibrated feeler gauge in the BDC piston position. This gap may increase beyond the permissible limit due to a decrease in the thickness of the contacts (burnout, grinding during cleaning). It is adjusted to 0.2-0.4 mm by turning the adjusting screw using the eccentric, with the pad of the entire breaker loosened.

But a spark occurs at the moment the contacts begin to connect, so its adjustment is more important than the maximum gap at BDC. When the piston does not reach TDC 4 mm, the breaker contacts should begin to diverge. This position is also adjusted by turning the screw using an eccentric. Most often this point is checked visually.

For more precise adjustment, you can use a 12 V indicator light with two wires powered by a battery.

The battery negative is connected to engine ground. One wire of the light bulb indicator is connected to the battery positive. The second wire of the indicator light is pressed against the body of the movable insulated contact. If the contacts are closed, the light shines.

Lightly turn the flywheel by hand. As soon as the contacts open, the light goes out. This is the moment the contacts begin to connect and a spark forms. The piston at this moment should be in a position that has not reached TDC 4 mm.

It is important not to confuse this with the position where TDC has passed by 4 mm.

Ignition of the chainsaw. Device, circuits, malfunctions.

How does a chainsaw ignition work?

The design of the ignition system of modern chainsaws

Magneto Stihl MS 180

An equally important fact is the reliability of modern systems. If earlier the ignition failed very often, now all its components are so durable and high quality that they rarely need repairs.

The chopper and the primary winding of the coil are connected in series. The switch is turned off due to the presence of a cam on the crankshaft. The primary winding is connected in series not only to the breaker, but also to the shutdown button. The magneto is mounted in the crankcase on the left, secured at the base with two studs and nuts.

With the help of flywheel magnets, a magnetic field is generated that crosses the coil. Due to this, if the contacts in the primary winding are closed, a weak current is generated. Accordingly, when the contacts are open, there is no magnetic field and an EMF is induced in the secondary winding. Due to this, a high voltage current is generated, which is supplied to the spark plug and gives a spark to ignite the fuel. At this moment, the piston is almost near top dead center (4 mm below it).

Ignition device for chainsaws “Ural-Electron 2 T” and “Druzhba”

The Ural-Electron 2 T or Druzhba chainsaw engines, as well as the Taiga-214-Electron, have a slightly different ignition system. Yes, they are used there

electronic magnetos of non-contact type. That is, they do not have a contact mechanical breaker.

What does it mean? The induced current is generated by a high voltage transformer. Moreover, its primary winding has a series connection with the thyristor through the charging winding, a capacitor diode, and also a control winding. Due to such a complex system, current passes through the thyristor only when a certain electrical potential reaches it.

As soon as the thyristor is open, the capacitor is discharged to ground. While a current with a large impulse passes through the primary winding, the secondary one creates a large inductive voltage, which causes a spark at the spark plug. That is, due to the thyristor and the control winding, a contactless breaker operates, which has high reliability, since it has no wearing parts.

Ural chainsaw ignition circuit

Ignition circuit for the Ural chainsaw (MB-1)

Ignition circuit for the Druzhba chainsaw

Druzhba chainsaw ignition circuit

Basic malfunctions of the ignition system of chainsaws

Having roughly understood how the ignition system of Chinese or domestic chainsaws works, you can already figure out what problems there may be with this mechanism and how to fix them.

Spark plug

Most often, breakdown occurs due to the spark plug. It is worth checking whether the insulator is damaged and whether the electrode is worn out. The entire spark plug is checked for integrity and absence of defects - this includes the integrity of the wires from the coil, the presence of insulating material, etc.

High voltage wire

Next, check the spark plug wires. Often they can run in such a way that there are many bends. In those places the wire can be damaged, while outwardly looking perfect. Next, inspect the spark plug cap and ignition wire. There should be no brown coating on it. If there is one, this means that the spark does not shoot in the right place, but in all parts near the ceramic insulator. The cap may also have damage - cracks, chips. The check must be carried out carefully, because a damaged insulating layer can result in an electric shock.

Model range of chainsaws Druzhba

The advantages of the Druzhba chainsaw, in addition to those mentioned above, are that it cuts smoothly and accurately, is highly productive and all the parts are in a durable case. Its disadvantages include significant weight - more than 12 kg with dimensions of 86.546x50 cm and a cable starter.

The main difference between modifications of the Friendship chainsaw is engine power:

Friendship 2 has a power of 2 kilowatts, manual start and, unlike the 1st model, an element for chain braking.
Druzhba 4, which received “gold” at the World Technology Exhibition in Brussels in 1958, has almost one kilowatt more power, sawing effortlessly, with shaft revolutions of more than five thousand, a half-meter log in one minute.
Friendship 4M-electron, having a non-contact electronic ignition system, uses the engine resource with greater efficiency, with almost the same power - 3 kW. The cylinder's chrome coating adds wear resistance, and rubber gaskets reduce overall vibration. In modification 4A, an oil pump is installed for forced lubrication of the chain.

Like any other technical device, the Druzhba 4 chainsaw requires constant carburetor adjustment, attention, regular care and preventive maintenance. At least once a year it is necessary to fine-tune the Druzhba 4 carburetor, including its adjustment.

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:

Dear readers, if you have any questions, please ask them using the form below. We will be glad to communicate with you

The production of Druzhba chainsaws began in the USSR in 1955 at two factories - ZiD (Dzerzhinsky plant) in Perm and Sibpribormash in Biysk. At the time of its launch, it was one of the most successful designs of a hand chainsaw. Therefore, in 1958, Friendship was awarded a Gold Medal at an international exhibition in Brussels.

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.

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;

Finalization of Friendship 4

Many Western chainsaw manufacturers produce tuning kits for their saws to increase power, and service centers have a separate price list with a list of possible modifications. Mainly found in petrol tool service centers in the USA and Germany.

It is also possible to modernize and replace components in order to improve the characteristics of saws from the Druzhba family.

Examples of what can be done:

Install turbocharging to increase the rate of supply of the fuel mixture;
Install a more modern carburetor;
Increase the compression of the fuel mixture;
Install an electric starter;
Bore the internal combustion engine and install an enlarged piston;
Install the decompression valve;
Leave one piston ring to reduce cylinder running resistance.

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.

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.

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The operation of the Druzhba-4 chainsaw revealed a number of shortcomings. What is especially annoying is that it is almost impossible to start a hot engine.

The cause of this “illness” is a weak ignition system.

To increase the power of the spark on the spark plug, the ignition system must be redone. Such a modification can also be useful in the absence of a working magneto coil for the standard ignition system.

For the modification, the low-voltage and high-voltage windings are removed from the standard magneto coil. Instead of low-voltage winding with PEV-2 wire with a diameter of 0.8 mm (this type of wire is used for winding transformers, chokes, etc.), 250 turns are wound. Interlayer insulation is required: after each layer of wire, a gasket is made of paper or varnished cloth. The beginning of the winding is soldered in place of the standard terminal to the core, and from the end of the winding a terminal is made with a mounting wire for connection to the ignition breaker. The coil is insulated on top (you can use insulating tape).

The circuit of the capacitor connected in parallel with the breaker and the coil remains unchanged.

Next, conclusions are drawn using two mounting wires through a piece of rubber hose as a seal. To ensure reliable insulation of the wires, it is advisable to combine them into a common sheath of PVC tube.

A B-115 ignition coil with a remote resistor, which is attached to the side of the coil, is used as a step-up transformer. This type of coil is found in the ignition systems of Moskvich, Volga and other cars. The use of motorcycle ignition coils is undesirable: they do not provide sufficient spark power. The ignition coil is attached using a clamp to the chainsaw frame in any convenient place.

The wires coming from the engine “snail” are connected as follows: one, coming from the common connection point of the capacitor, breaker, coil output - to the “VK” terminal of the B-115 ignition coil; the second, coming from the ground and connected to the magneto mounting bolt - to the terminal of the B-115 ignition coil, which does not have a designation. It is advisable to choose wires of different colors.

Next, the ignition coil is connected with a high-voltage wire to the engine spark plug.

Adjusting the ignition timing gave very good results, all the “illnesses” of the chainsaw disappeared. For several years now, the redesigned ignition system has been working properly on the Druzhba-4 chainsaw.

In conclusion, we can say the following: the ignition coil slightly “spoils” the appearance of the saw, but it is better to have a saw that is reliable in operation than one that brings nothing but torment.

This ignition system can also be used on other types of engines, which was tested on moped engines of type D-5, D-6. The winding in this case contains 160 turns.

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.

Chainsaw models

The overall design of the saw has not changed significantly over time, only individual parts have been modified. The number at the end of the model name indicates its power, for example, Druzhba 2 - 2 hp. In the first chainsaw produced, the handles were attached to the fan cover; later they began to be attached to the clamp that connected the gearbox and the engine. Model 4A, produced until the 80s, already used a contact magneto and a KMP-100 carburetor. Automatic chain lubrication was also used for the first time. Later it was discontinued and instead they began to produce the 4A-Electron model with electronic ignition.

In the 90s, the previous carburetor was replaced with a new KMP-100U. The chain saw became known as Druzhba-4M and was equipped with updated chains. Based on the Druzhba chainsaw, the Ural saw with more powerful characteristics was developed. The latest model produced with a similar design is Druzhba 5E.