Electronic ignition for a chainsaw with their own hands

The device of a chainsaw by scheme and in section: from pressing the start, to the movement of the chain

On the completeness of the understanding of the device of the tool depends on both the efficiency of work and the duration of its service. At first glance, the classic chainsaw may seem like a complex technological device, but the principle of its operation is based on mechanics and is available to anyone who wants to understand it. In this article, we’ll take apart the construction from A to Z, show each component and explain popularly its operation and role in the system.

The chain saw is based on a simple internal combustion engine with a single cylinder that is fuel-injected. Petrol with dissolved oil, dosed from the tank into the carburetor, from where it travels to the engine, where it is ignited by the spark created by the spark plugs. This controlled explosion in a sealed chamber, pushes the piston connected to the crank and shaft. Next, the rotary motion is transferred to the clutch and sprocket, which hooks onto the chain, making it move along the groove of the saw bar.

The above sequence is just a basic outline of how a chainsaw works. The complete list of components goes far beyond the standard internal combustion engine parts, including important ancillary components. The oil pump, starter motor, flywheel brake, clutch, ignition system and chain tensioning are indispensable components that make the saw very effective. The scheme of a chainsaw, shown below, clearly demonstrates the key elements, the purpose and interaction of which is described in detail below.

All chainsaw components

You don’t understand how a chainsaw works until you have become familiar with its multifaceted design. By taking apart each part and thinking clearly about its function, you can easily build a complete picture of the whole mechanism, which will help in further use or when repairing the tool. After reading this material, you will have a clear understanding of the inner workings and functions of a classic gasoline-powered chainsaw.


The first organ of the chainsaw, with which the device begins to work. This is the assembly responsible for starting the engine, which takes place by rotating the crank shaft with the flywheel, which generates an electrical impulse. The starter consists of a drum with a return spring and a wound cable connected to a lever. When the lever is pulled, the drum unwinds, transmitting motion to the shaft to which it is connected. At the slightest decrease in tension the spring returns the reel to its original position, winding up the cable.

The starting process requires precise, jerky movements and usually does not start the engine with the first pull of the cord. On average, in order to start the machine, it is necessary to repeat the jerk 2-4 times. In order to facilitate and accelerate the procedure, modern chainsaws are equipped with auxiliary elements. The most common method is based on enriching the fuel mixture by closing the air valve in the carburetor. Also, the cylinder can be equipped with a decompression valve, which reduces the pressure and facilitates cranking of the shaft. On some models, an additional spring is added to the reel that continues to rotate when the cord is fully extended.

Ignition system

The next design node, which ensures the generation of an electrical impulse for the subsequent ignition of the fuel in the cylinder. On the first gasoline-powered saws, this system was of the contact type and required periodic cleaning and adjustment of the gap between the handwheel and the ignition module. Today’s units use non-contact electronic systems that require no such maintenance.

The key components of the ignition are the flywheel with magnets, the coil with the core, the electronic unit, the high-voltage wire and the spark plug. As the flywheel rotates, magnets act on the coils in which the electromotive force is induced. The current received, passes through a wire to the block, where it is converted into an electrical impulse. Then, through the high-voltage wire, the charge is transmitted to the spark plug, which creates a spark that ignites the fuel mixture.

Fuel system

Special fuel storage area built into the chainsaw’s design, providing filtration and a convenient fuel supply. To avoid increasing the weight of the instrument, the fuel tank volume is normally limited to 500 ml. The tank design includes a hose, filter, and breather. Fuel goes through the filter attached to the end of the hose before it enters the carburettor. When the volume of fuel decreases, air enters the tank through the breather, so that negative pressure is not created in the tank.

If the breather on the chainsaw is clogged, the carburetor pump will not be able to pump fuel and the tool will simply not start. As the saw is used, the fuel filter also becomes clogged, reducing its capacity and causing engine malfunctions. If the breather can be cleaned yourself, the filter is recommended to be replaced as an expendable. The frequency of replacement depends on the quality of the fuel mixture and the intensity of use of the tool.

Carburetor assembly

The main distributor element of the chainsaw, responsible for pumping fuel from the tank to the engine cylinder. In modern carburetors, the pump function is performed by a diaphragm, which in older models (Druzhba, Ural) was absent and gasoline entered them by gravity, which did not allow the tool to tilt during operation. Nowadays, the most popular carburettor assemblies are produced by companies Walbro and Zama, which are characterized by high durability, with responsible air and fuel filtration.

Nowadays, almost all chainsaw models are equipped with classic carburetor types with a choke, diffuser and inlet nozzle (basic elements). 2 or 3 adjusting screws can be brought out on the cast housing, to adjust the RPM and fuel supply. Increasingly, there are designs where the carburetor is connected to an external hand pump (primer) to facilitate starting.

The structure of the chainsaw primer is a sealed silicone dome, connected to a plastic base, which has 2 nipples. 2 hoses are connected to the base: the first one draws fuel from the tank and the second one supplies fuel to the carburetor float chamber.

Main malfunctions and troubleshooting

If you can’t start the saw right away, there are several possible reasons. Most often the problem is related to the spark plug:

electronic, ignition, chainsaw, hands
  • Wear of the electrode or damage of the ceramic insulator;
  • Loose fit of the removable cover (if present);
  • Wandering of the spark along the ceramic winding, a sign of which is a brown residue on the outer sheath;
  • Cracks in the spark plug cap (a saw with this problem will still work, but may hurt the user when touched).
electronic, ignition, chainsaw, hands

If no problems are found with the spark plug, it is advisable to inspect the wires coming from the coil. They may be broken or have other mechanical damage. There may be broken wires inside the insulation, so sometimes these faults cannot be detected by visual inspection.

The cause of the problem can be found in the off switch. They are easy to check. To do this, you must disconnect the wires from the module, and then check the ignition. If after disconnecting the ignition switch the spark is still there, then the switch must be replaced.

Causes of problems

When chainsaw does not start on the first try, it is recommended to inspect the wires that are connected to the coil. This is how you can detect:

Important! Damage to the internal insulation cannot be identified on inspection.

If in the initial assessment of the coil is all right, you need to look for the cause of the breakdown in the tumbler (you need to disconnect the module from the wires). Don’t know how to check the ignition on a chainsaw? For starters:

  • Evaluate the condition of the electrode (it can fail due to wear and tear), check the integrity of the ceramic insulator;
  • Inspect the removable valve, which must fit tightly (it is not removable in all models);
  • A brown residue on the winding ceramics indicates a stray spark;
  • Looking for a crack in the spark plug (the cap sometimes cracks).

Soviet chainsaw ignition Carefully inspect the coil for traces of fuel. The spark plug should be dry (traces of deposits present should be a light color). If you find excess fuel, the problem could be the carburetor, which, by feeding a large amount of gasoline, floods the spark plug. In addition, fouling can also indicate changes in the geometry of chain saw components such as the piston and cylinder.

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A Careful Check

If the preliminary assessment of the state of the coil did not give results, you need to conduct a thorough diagnosis.

  • Experts recommend taking a multimeter and checking the resistance level of the coil. Check the optimum values for your model (this information is in your chainsaw’s manual). Keep in mind that sometimes the “test” ends with a “break in circuit” reading, do not panic, as many saws use semiconductor parts. A positive test result indicates the presence of a fault.
  • Checking the electrical circuitry for proper functioning. The cable is leaning against the gap between the cylinder and the coil. If there is no spark breakdown, you can conclude that the high-voltage cable is faulty, damage to the internal insulation.
  • Checking of spark presence (a special device is also used). A testing device is placed between the coil lead and the bulb of the spark plug (this place is called the circuit break). Pay attention to the data displayed on the screen of the meter, compare it with the optimal for your chainsaw. Not everyone can afford this method of testing in the “home”, as special equipment is expensive.
  • Making a homemade ignition. This test assumes the use of a spark plug. It is taken out and leaned against the cylinder housing, while starting the starter. Watch the spark. The method is not the most reliable because of the non-standard speed of rotation of the flywheel (because the position of the spark plug is unnatural), but it is actively used by many craftsmen.

In the field, when the above methods of checking the ignition are not available, resort to this method.

  • The method requires a nail without a hat, which is placed close to the cylinder. 7 millimeters from it. Be careful not to damage the part.
  • Pull the starter and watch the spark. If it appears and is bright, there is no malfunction.

The method is useful if there are no electronic nodes. Other than that, you’ll have to follow these rules.

  • Do not unscrew the spark plug completely, so as not to speed up the rotation of the flywheel. This will have a negative effect on engine operation.
  • The spark plug is placed so that the distance between it and the cylinder was not less than that recommended, taking into account the saw compression model and dielectric properties of the fuel mixture used (on average, place at a distance of 7 millimeters).

Chainsaw ignition repair

Having considered the main types of faults and explained how to check the magneto chainsaw in different ways, you can move on to the main thing. the repair of individual nodes of the ignition system. The following instructions are given in increasing order of difficulty of repair, but if you already know the cause, you can skip straight to the analysis of repairing your problem.

Restoring the spark plug

Even the slightest deviation from the fuel mixture requirements or improper adjustment of the carburetor, can be a significant cause of the loss of spark. During the use of the tool, on the contacts of the plug gradually forms soot, an excessive amount of which completely obscures the metal, putting an end to further work. Detect such a violation is very simple. you just unscrew the plug from the socket.

The best way to clean spark plugs is based on the use of chemicals. For this purpose will do penny dimexide (available at drugstore) or Cillit BANG (at the “grocery” store). products). Simply place the spark plug in an ordinary beaker and fill up so that the contaminated contacts are completely in the solution. After 30-60 minutes of marinating, clean the contacts with an ordinary toothbrush. The use of metal brushes or sandpaper, with a high probability will lead to the formation of scratches on the contacts and ceramic insulator. The scratches, if used later, will tend to deposit more easily, resulting in faster fouling.

The coarse method of cleaning is recommended when the fouling is excessive, when chemicals alone will not do the job.Except for an excessive layer of contamination, the spark formation can be prevented by an increased contact gap. Strong vibrations in conjunction with heat, deform the arc fixing the side electrode, reducing or conversely increasing the distance to the central electrode. Optimal spark plug gap for chainsaw spark plugs is 0.5. 0.7 mm. You can adjust the position with the pliers, and use an ordinary plastic card as a template.

Adjusting the clearance between the coil and the flywheel

The constant vibration of a running engine, has a negative effect on the fixing elements, gradually disturbing the fixation of the components connected to them. One of the first breaks the adjustment of the chainsaw ignition, which requires the most accurate position in relation to the flywheel. On average, the distance between the ignition coil and the handwheel should be from 0.2 to 0.4mm. Exact values for setting are usually given in the technical documentation of the specific saw model, but if such data is not available, it is better to make a gap of 0.3 mm.

To adjust you will need a screwdriver with a basic set of interchangeable bits, an improvised spacer (paper or a piece from a regular plastic bottle) and blue thread locker (ideally).

The first thing to remove is the left, side part of the saw body that hides the elements we need.

We find and loosen the screws that fix the ignition coil. To be safe, it would be better to unscrew them completely and put a threadlocker on the threads to prevent unscrewing in the future.

Install the spacer between the handwheel and the module. You can use any means at hand: a sheet of notebook paper (1 ≈ 0.05 mm), cardboard from a cigarette packet, a piece of plastic bottle.

We turn the flywheel with magnets to the contacts of the coil, between which the spacer is already located. The last coil should be magnetized.Tighten the fixing screws with a little more force than average (without fanaticism).

Remove the spacer and check the flywheel rotation. the stroke must be free, without any hint of contact with the coil.

The adjustment process is complete and now you know how to set the ignition on the chainsaw, using a screwdriver and handy spacer tools. If the coil is in good condition, the spark is sure to show up. If this is not the case, the following instructions must be used.

Replace the armature coil wire

When the electrical impulse is lost before it reaches the spark plug. The fault lies in the transmission unit. To restore the damaged insulation of the high-voltage wire is quite possible, but not all places (especially in the bends) it is realistic to build up without violating the principle of laying. For situations where restoration is unacceptable, the best way out will be to replace the damaged armature wire, with a new one.

  • Unscrew the ignition coil and remove it along with the wire for further work. To easily remove the cable without taking apart any part of the case, remove the candlestick cover and the spring.
  • Carefully remove insulator in place of contact (it will be useful) and bite off wire practically at the magneto.
  • Grind the cut with a file or an abrasive wheel to obtain an even surface.
  • Take a small self-tapping screw ≈ 4 x 25 mm and screw it into the magneto in place of the wire halfway.
  • Bite off the head of the screw and sharpen the opposite end, so it can be screwed in. It is possible to make manually, file, angle grinder or on a sharpening machine.
  • Screw the end of the new armor wire onto the self-drilling screw up to the stop and put on the previously removed insulation. For reliability, you can better glue it.
  • Install the ignition module in its place, lay and lead the wire to the spark plug.
  • Install the spring by piercing the end of the wire on 2 sides and put it through the cap of the candlestick.

Weak spark on a chainsaw

Since the introduction of the new ignition system in the tool, the opinion that a low-power charge is not capable of igniting the fuel mixture has not receded. Usually, such a statement is based on a comparison with old coils generating a pronounced blue spark. The charge of modern modules has a much paler shade and a smaller range of action, which may raise doubts about its effectiveness, relative to its powerful counterpart from the past.

Effective mixing of air and fuel, forms an extremely combustible substance, which is quite enough when a weak spark is given out on the chainsaw. The reason for the decrease in charge is to optimize the operation of the coil and reduce its size. If the spark is there, the mixture will ignite 99% of the time, with normal gasoline, oil, and a functioning carburetor.

Repair with your own hands

When the above measures do not eliminate the problem, the causes may be. Block of electronic ignition fails. All elements of this unit are sealed (filled with compound) and can not be repaired. Requires replacement of entire unit.

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

  • The tex-thick insulator of the movable contact of the shearbolt is pierced to the common ground. It is replaceable without variant.
  • Burned out mobile and fixed contacts of the chopper (cams). Cleaned with a fine nail file or emery cloth until the surfaces are evenly contiguous. Replace at complete burnout.
  • Capacitor is designed to protect the contacts from burning out. Fails rarely, does not directly affect spark formation. It is simply ignored during diagnostics.
  • Inter-turn short circuit, breakage in secondary high-voltage turns of coil with thin wire.

How to adjust ignition on Druzhba

The spark on the candle must flare at a precise moment. On Druzhba. when the piston with a portion of the fuel-air mixture approaches the plug, not reaching 4 mm to TDC. Only with a fine-tuned spark plug timing will the engine run properly. Deviations are called early or late ignition.

With small deviations in one direction or the other, the engine will run worse (underpowered, overheating, fuel overrun, poor starting). With more significant will not work at all. May shoot into the exhaust system or carburetor.

The mechanical chopper of the Druzhba chainsaw is regulated simply.

Before adjusting, you need to check. perhaps the fastening of the entire system platform is loose and it has turned. Checked by the coincidence of the factory marks (marks) on the metal base of the ignition and the engine crankcase. These are usually stamped as strips on the upper right side of the ignition and should match. If there is an offset, it is corrected.

the maximum clearance (at the divergence peak) between the cams (pins) should be 0,2 to 0,4 mm. Ideally 0.3 mm. Check with a calibrated feeler gauge at the bore position. This gap may be increased beyond the allowable gap due to thinning of the contacts (burn-out, grinding during cleaning). It is corrected to 0.2-0.4 mm by turning the adjusting screw due to the eccentric, with the whole shearbolt pad loosened.

But the spark arises at the moment when the contacts begin to separate, so its adjustment is more important than the maximum clearance at NTM. When the piston is less than 4 mm from TDC, the pistons should start diverging. this position can also be adjusted by turning the screw by means of the eccentric nut. This point is most often checked visually.

A 12 volt indicator light with two leads connected to a battery can be used for fine tuning.

Connect the battery minus to the engine ground. One wire of the indicator light bulb is connected to the plus of the battery. The second wire of the indicator lamp is pressed to the body of the movable insulated contact. If the contacts are closed, the light bulb is on.

Repair of the ignition of a chainsaw Ural with his own hands

In some lespromkhozes, as well as in individual farms still use chainsaws “Ural-Electron” and “Druzhba-4-Electron”, the engines of which are equipped with an electronic ignition unit. This unit is very simple in circuitry, but, like other machinery, sometimes fails. Replace it with a new one. It is expensive, especially since the industry now produces magnetos of such quality that they last one day of operation, or at most one weekAny radio amateur is quite capable of repairing this unit himself.

Block diagram option 2 (often used).

L1. a generator coil, d=0,063mm, W=11000 turns, R=3000 ohm; L2. a control coil, d=0,1mm, W=1200 turns, R=80 ohm; T1. high voltage transformer, d1=0,28mm, W1=75 turns, R1=0,5ohm, d2=0,063mm, W2=6900 turns, R2=2000ohm;E. electronic unit;C1. capacitor 0,47μf 630V;R1. 390 ohm resistor 0,25 W;V1-V5. diodes. correspond to KD 209;V6. thyristor corresponds to KU 202

Before you start the repair, it is necessary to determine the circuit of the ignition unit. Variant one. It is necessary to measure the resistance of the generator coil L1 and the secondary winding of transformer T1, the resistance of the control coil L2 and the primary winding of transformer T1, it is not necessary to measure, it is enough to check them for breakage. Then check if the thyristor control circuit is OK, by measuring the resistance. connect one probe to the soldered pin to the resistor R1, the second probe to the common ground. In one direction the resistance should be equal to the sum of the resistances of the resistor and diode forward junction V5, approximately 2. 4 com. In the other ∞. In case of good condition of all windings and thyristor control circuit, you should make a drilling with diameter of 1,5. 3 mm at the connection point of thyristor anode V6 with the capacitor C1 (point A), and unsoldering coils check diodes V1-V4, and capacitor C1 for good condition. If one of the diodes is defective, you can solder it by hinged mounting, preliminarily destroying the old defective diode, by drilling. It is better to use a drill for this purpose. If the capacitor C1 is faulty, it must be removed, a new one must be inserted and the lead soldered to the indicated point, then filled back in with epoxy glue. If thyristor is defective, I recommend you to replace all circuit of the unit, before removing the old one, solder it by hinged mounting and fill it with epoxy glue.

Additionally, if the resistance of the thyristor control circuit is greater than normal, probably violated the contact circuit with the ground, to restore the need: to free from adhesive bolt M3, unscrew it, clean the contact and re-screw, but a new one (point B), or just solder the hinged conductor, connecting it to the magneto housing. If the saw works, at high RPM intermittently, you need to replace the transformer T1. If after a few minutes of operation completely lost the spark. this points to a faulty thyristor V6, you must replace the circuit. Variant two.If the coil windings are intact (the resistance of the generator coil with one lead may be ≈1 kohm, this is normal). check if the capacitor lead soldered to the T1 transformer lead is broken. If all elements of the circuit are working properly. I recommend to turn over the generator coil, putting the lead wire. If you have a defect in at least one element of the circuit, it is better to replace the circuit completely, soldering it according to the scheme of variant 1, winding the coil with two leads. If there is no generator coil, with two leads, you can install with one lead, but on the insulation. It is enough to drill out the pipe rivet with a drill Ø5,1 mm and put a PVC pipe Ø4 mm and put fiberglass washers and a mounting disk, for the second lead, when assembling.

At replacement of elements good results are with diodes 1N4007 and thyristors KU709B/KU712B. In principle, a diode can be put in parallel with a thyristor. this will slightly increase energy and duration of spark. To increase these characteristics even more, you can replace half-period rectifier by a bridge; the above-mentioned diode is not needed in this case. It is desirable to set the thyristor response level at 600-700 rpm. it will provide a bigger range of ignition timing advance angle (now I believe they say: torque) regulation at the cost of insignificant worsening of cranking. In any case, after replacement of thyristor or elements in the circuit of its control electrode, ignition advance angle setting will practically always be disturbed, which, in the absence of a stand, will require additional adjustment on the engine.

On ignition timing adjustment. The control pulse generated by the control coil has a bell shape. in the first approximation is similar to a sine quadratic. So, when the handwheel speed increases, the amplitude of this impulse increases, and at some speed it is enough to start the thyristor, i.e.е. reaches the start level (I like the term “actuation level”). At this speed the thyristor response level is naturally in the pulse apex area. With further increase in flywheel speed the drive pulse continues to increase, while the thyristor actuation level remains constant. This leads to the fact that the control signal reaches the thyristor actuation level not at the apex, but earlier. at the rising edge. Т.е. as the range of the control pulse increases, the moment of its equality to the actuation level of the thyristor moves from the apex on the leading edge to the beginning. The ignition torque changes accordingly. The typical value of this change when the flywheel speed changes from the start of spark formation to 5000 rpm is about 15 degrees; with careful adjustment it is possible to get 19. 20 degrees. This is the regulation which is provided automatically. But there is also the well-known tuning by rotating the base of the magneto in the socket. is a kind of zero setting: just a compensation of the variation of the magneto elements in order to obtain a given ignition torque at one point (if I’m not mistaken, at 5000 rpm)

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What does this sentence mean: “It is desirable to set the thyristor actuation level to 600-700 rpm”. and how do you realize it and by what marks can be set, in this case, the ignition timing with an ordinary stroboscope?

Operation, Service and Repair

To keep your saw running smoothly, it needs to be tuned periodically. The instruction manual which is enclosed to the machine describes the peculiarities of the adjustment of the model. Improper adjustment will result in unbalanced operation.

How to adjust the carburetor

Failures occur when not enough or too much fuel is delivered, and also when the proportions of fuel and air are mixed incorrectly.

Carburetor adjustment is done as follows:

  • The fuel adjusting screw is first turned to its stop and then backwards (counterclockwise) by 1.5-2 turns.
  • Start the engine, warm it up for 1-2 minutes and turn the screw T in one direction or another to achieve its stable operation at maximum speed. The circuit, when idling, must not move on the bar.
  • Check and, if necessary, seal carburetor-cylinder connection.

It is easier to adjust the carburetor, using a tachometer, but at home the work of the engine in most cases is adjusted by ear. When both quantitative and qualitative fuel supply are normal, the engine doesn’t overheat, doesn’t bog down, runs smoothly, without any harsh sounds. When adjusting, the screws turn slowly, without jerks.

How to set the ignition

Stable operation of the engine provides properly adjusted ignition. the Druzhba 4 chain saw will then consume a minimum amount of fuel. The saw is ignited thanks to a magneto using a spark plug and a special wire.

To trace the quality of the spark to ignite the chainsaw, the spark plug is placed on the cylinder housing and pull the starter. If the spark plug is in working condition, there will be a spark between the electrodes. Weak spark will not cause fuel ignition, such a spark plug must be replaced.

It is better to replace the contact ignition of a chainsaw with an electronic one. This will save you from constant problems with its adjustment. It is necessary to make sure that the screws fixing the ignition coil do not loosen.

Main malfunctions and remedy

If you know why the tool fails, you can repair it yourself at home.

When the engine of the Druzhba 4 chainsaw starts and stops, the reasons may be:

  • Not enough fuel in the tank. Fill up the spark plug mixture according to the enclosed instructions.
  • The spark plug is spattered with fuel. This keeps the spark from forming. The spark plug should be taken out, dried, heated on a gas torch.
  • Poor contact between spark plugs and wire. This is caused by an increased gap (more than 0.5 mm) between the tip of the spark plug and the wire. The spark plugs should be cleaned of carbon deposits with a wire brush and blown with air. You need to change it from time to time.

If the engine malfunctions at idle speed, the Druzhba 4 chain saw repair is reduced to the following:

  • changing the fuel mixture with less oil;
  • cleaning the air filter and muffler (because of its clogging, the engine works, but does not develop revolutions);
  • check the fuel line and change the tube if necessary.

If cutting speed slows down, bar starts to “wobble”, check sharpness of saw blade teeth. A well-sharpened chain is more important than a strong engine. It is best to surrender it to the master for sharpening or use a machine with a rotary sharpening disc. The blade bevel of the Druzhba is 45° on the lower edge and 60° on the side. the height of the limiting tabs relative to the chain teeth should be the same and checked after 3-4 sharpening of the chain.

It is recommended to put the chain for some time in the liquid lubricant, preferably warmed.

The reasons why the Druzhba saw does not start, may be the following:

When assembling, even if the parts sit tight, you can not use force, such as knocking on them with a hammer. By replacing worn elements, it is possible to restore the performance of the chainsaw or extend its resource.

Druzhba chain saw ignition modification

Since the engines on the Druzhba 4A and Druzhba 4A Electron chainsaw models are absolutely identical, it is possible to interchange contact and electronic ignition systems on all models.

And sometimes it is possible to redo the failed coil of the old contact ignition, and install it instead of the failed electronic version.

Contact ignition coil modification

Remove the coil and remove all unusable high-voltage secondary winding made of the thinnest wire. The primary winding, consisting of several turns of high-power wire, almost never fails. It is left in place.

The main thing is not to damage the insulating layers of lacquer when disassembling.

Instead of the removed winding use remote high-voltage coil (bobbin) from a motorcycle, a two-speed moped of the Soviet period, the car. The coil is fastened in any way in a convenient place. Restore the wiring diagram as it was with the stationary winding:

The disadvantage of this option. on the body of the Druzhba chainsaw there will be an additional detail.

The advantage is that high-voltage coils are easy to change, they are available.

Also in the network you can find descriptions of how to repair the electronic ignition system of the Druzhba, which is reasonably considered almost unrepairable. This is also possible, but you need to be experienced in electronics and electrical engineering.

The following video tells about the ignition device on the Druzhba chainsaw, which also gives recommendations on adjustments:

For the inhabitants of the USSR, the Druzhba was the only chainsaw, always in short supply, but relatively affordable. (Ural was created on the basis of the Druzhba as a more powerful version for the timber industry). Hundreds of thousands of Friendships have been issued over the decades. Many of them, due to good repairability, are still in working condition. And parts, including ignition systems of two kinds, can still be found at flea markets and even online at sites like Avito.

You can choose any convenient way of payment/delivery. Prepayment. delivery the next day after receipt of funds to our account;

Under the agreement of deferred payment. delivery the next day at the confirmation of order until 15:00 of the current day. Payment for goods after receipt within 5 calendar days

Cash. delivery the next day if the order is confirmed before 15:00 of the current day. Payment upon receipt of goods.


Over the 60 years of production, the Druzhba chainsaw design and characteristics have not changed much.

  • weight when fully equipped. 12.5 kg;
  • dimensions. 865x460x500 mm;
  • saw bar length. 450 mm;
  • the capacity of the fuel tank is designed for 1.5 liters of fuel;
  • Spark plug. any with a diameter of 17 mm.

The main difference between the modifications. in power. It is indicated by a number in horsepower at the end of the model name.

Druzhba 2

The technical specifications of this model are as follows:

From the first model of the Druzhba 2 differs existence of the device for braking the chain, which made it safer: the tool can not hurt the person working or people around him accidentally. The material of the body is reliable and can withstand all temperature changes.

Druzhba 4

This model has won a gold medal at the World exhibition of technology in Brussels in 1958.

Specifications of the chainsaw are as follows:

Petrol-powered saw can cut a trunk diameter of up to 50 cm in 1 minute.

Druzhba 4M electronic

Druzhba 4M electronic chainsaw differs in that this model is equipped with a contactless electronic ignition system, which significantly increases engine reliability.

The inner walls of the aluminum cylinder liner are coated with chrome to increase wear resistance. The model is equipped with rubber shock absorbers that reduce transmission of engine vibration to the handles. In the Druzhba-4M model the KMP-100U carburetor is used, and with the Druzhba 4A modification the use of the chain compulsory lubrication has been introduced due to installation of an oil pump. It allowed to increase greatly the lifetime of chain and guide bar.


Engine. single-cylinder two-stroke carburetor. Cooled by air flow created by centrifugal fan. Motor and saw unit are independent units joined into one unit by flange fasteners and secured by a clamp.

When you open the fuel tap, fuel flows into the diaphragm carburetor, which ensures uninterrupted fuel supply to the engine at all angles of inclination and strong vibration. The design of a chainsaw does not allow the engine to stop when the chain jams in the trunk while cutting wood.