Ural Chainsaw Carburetor Adjustment
The Ural chainsaw is still in service
The Ural chainsaw was first produced in 1935. In 2005, at the F.E. Dzerzhinsky in the city of Perm collected the 14 millionth copy of the legendary instrument. 80% of logging in the country is still carried out using the Ural chain saw. At the same time, a model for small work on farms comes off the assembly line. the Druzhba saw, but it is a class lower than its older brother.
Characteristics of a chain saw of the Soviet era
Initially, the Ural chainsaw was on the technical equipment of the army, and only in 1955 the plant switched to production for felling, giving the model the name Ural 2. The tool weighed 11.7 kg. At the same time, the engine power was 5.5 liters. C. The saw blade rotated at a right angle during operation, which facilitates the work of fellers. The chain had a forced lubrication, a hydraulic wedge was included in the equipment of the unit.
The Soviet Union was in isolation, the equipment created was valued, and was distributed to the timber industry enterprises according to the order. The same distribution system did not allow private ownership of not only the Ural chainsaw, but also Friendship.
Technical characteristics of the Ural 2 chainsaw:
- Two-stroke engine, single-cylinder;
- Power. 5 HP FROM.;
- Fuel tank. 1.6 l;
- Saw unit lubrication tank. 0.24 l;
- Bus length. 46 cm;
- Chain, number of links. 64;
- Link pitch. 0.404 inches;
- Groove width. 1.6 mm.
An important condition for the long operation of the Ural chainsaw was its proper running-in. The initial start of the engine was carried out at idle with the use of an enriched fuel mixture. It was necessary to burn 4 full tanks of fuel. After 25 hours, it was prescribed to work in a gentle mode on the same enriched fuel mixture. After that, a working mixture was used in the composition of 20 liters of AI-72 gasoline 1 liter of oil.
Modern chainsaw Ural 2T Electron
The plant made some changes in the production of chainsaws, and the improved model was given a new name. The saw is still in service with forest workers and in private use. Reliable operation of the tool is evidenced by the 1997 model for sale.
Chainsaw 2T Electron is designed to work in difficult conditions at any time of the year. It is made of high strength materials. The tool can be used in an aggressive environment and at any outdoor temperatures. Therefore, a detailed step-by-step instruction has been developed on how to independently repair complex mechanisms in the field.
A powerful chainsaw has one special property that makes you come to terms with the shortcomings of the mechanism. It handles both cross and longitudinal cuts with ease. In addition, the tool is reliable, high handles allow you not to hunch over, to work at full height. On the other hand, having got acquainted with imported, professional equipment, experts see the shortcomings of the native model:
- The engine works with increased gas production, the feller has to work in a gas-polluted environment;
- The mixture is 2 times more enriched with oil than on imported machines;
- Saw maintenance requires experience and dexterity;
- Increased fuel consumption;
- No chain brake.
This is not a complete list of where the old technology is inferior to modern foreign models. The demand is supported by the low price of the Ural chainsaw. However, entrepreneurs prefer imported equipment. The plant announced the termination of production of the Ural 2E Electron chainsaw in 2013. Models are on sale from the manufacturer’s plant and are currently.
Running in the Ural chainsaw
Running in the Ural chainsaw began with idling until at least four full tanks were used up. In this case, the proportion of oil and gasoline for running in the Ural chainsaw should be 1:15, that is, for 15 liters of gasoline it is worth pouring 1 liter of oil.
After the saw has idled, run-in continues during operation. The chainsaw should not be fully loaded for 25 hours. The fuel mixture is prepared in the same proportions as during idling.
The mixing ratio of oil and gasoline for the Ural chainsaw after running in is 1:20. For 20 liters of gasoline 1 liter of oil.
Homemade from the Ural chainsaw
From the Ural and Druzhba chainsaws, folk craftsmen have collected many different devices. What is the story of a prisoner who escaped using a helicopter from a chainsaw? We will talk about these crafts in a separate topic. In the meantime, look at the 12-volt generator assembled from the Ural chainsaw engine and the generator from the Volga car.
Chainsaw generator Ural
Technical characteristics of the Ural 2T-Electron chainsaw
|Engine||gasoline single-cylinder two-stroke|
|Power, kW / hp.||3.68 / 5.0|
|Rotation frequency, rpm||6200|
|The gap between the electrodes of the candle||0.6-0.7 mm|
|Sound level dBA||105|
|Fuel consumption, g / kWh||632|
|Fuel tank, volume||1.6 l|
|Grease consumption, cm³ / min||42252|
|Oil tank for chain lubrication, volume||0.24 l|
|Sawing device working length, cm||46|
|Chain pitch, mm||10.26|
|Dimensions length / width / height||880/455/460 mm|
As you know, in the Soviet Union there were 2 models of gasoline saws. "Ural" and "Druzhba" and electric "Parma". If "Druzhba" was originally intended for private farms, then "Ural" was designed as a "professional" saw, especially for felling timber. Chainsaws "Friendship" and "Ural" have a similar design, but there are some differences.
Ignition adjustment of the Ural 2T-Electron chainsaw
The ignition is preset at the factory in the most optimal way! The ignition characteristics are given in the instructions that can be downloaded below. I’ll tell you how to set the ignition on the Ural chainsaw after removing the magneto.
Adjusting the carburetor of the Ural chainsaw
Chainsaw engine idle speed adjustment.
The adjustment is made by changing the quality and quantity of the combustible mixture entering the engine cylinder. The amount of the mixture supplied to the saw carburetor is changed by screw No. 3 (Figure 14), which limits the rotation of the throttle control lever 1 towards its closing. The quality of the mixture is changed by screw No. 1 (Figure 15) of the carburetor.
If you adjust the idle speed of the Ural petrol saw, proceed from the following manufacturer’s instructions:
A) The engine should idle steadily and evenly, and the saw chain should be in place. B) The engine should not emit a lot of smoke c) The engine should have good throttle response, that is, when the throttle control lever is pressed sharply, it should quickly and easily develop revs. D) The idle speed adjustment is performed in the following order:
- We start the engine and warm it up at low and medium speeds. Screw No. 3 (Figure 14)
- We set the minimum stable speed at which the chain does not move along the saw bar. If the engine smokes a lot (and this is a clear sign of an excessively rich mixture), then screw No. 1 of the carburetor must be turned until the rpm increases and the smoke from the muffler decreases.
- Then again we set the minimum speed at which the saw works for this. we unscrew screw No. 3 (Figure 14);
- After this adjustment has been carried out, it is necessary to check the throttle response of the chainsaw engine. To do this, we very sharply press the throttle control lever for a few seconds until it stops. In this case, the engine should quickly pick up speed. If the engine stalls or has a "dip" of power, ie slowly picks up speed (lean mixture), then screw No. 1 of the carburetor must be unscrewed by the required amount. The engine speed will decrease. To increase idle speed, screw No. 3
- Must be partially wrapped. Check the engine again for throttle response;
- At the end of the adjustment, screw 3 is fixed with special locknuts 2 (Figure 14).
Adjusting the engine to maximum power
This adjustment should be made after you have run in your "Ural" and adjusted the idle speed. The adjustment is made with the screw “2 (Figure 15) of the chainsaw carburetor, by depleting or enriching the fuel mixture while the engine is running in operating mode. When the adjusting screw is partially screwed in, the mixture is leaner, when unscrewed, it is enriched. The most optimal position of the screw number 2 of the carburetor is determined experimentally when working with a chainsaw.
If you adjust the idle speed of the Ural petrol saw, proceed from the following manufacturer’s instructions:
- The engine of the chainsaw must develop a power that ensures high cutting performance with a small amount of smoke.
- The chainsaw must have good throttle response, not overheat and not slow down and stop during operation (engine overheating is a sign of a lean mixture and engine overload).
- Due to lack of experience, cases of complete misalignment of the carburetor are possible, while the chainsaw stops working normally, it becomes difficult or impossible to start the engine.
- To restore normal adjustment, it is necessary to set the carburetor screws No. 1 and No. 2 (Figure 15) to their original position as follows: a) screw in the screw No. 1 until it stops and then turn it out by one turn; b) screw in screw No. 2 until it stops and then turn it out by ’/ 2 turns. After restoring the original position of the adjusting screws, adjust according to the methods described above.
The difference between the Ural chainsaw and the Druzhba chainsaw
- Great power. 5 h.P. Against 4 at "Friendship"
- Less weight. Ural weighs 11 kilograms and Druzhba 12.5.
- In the Urals, the gearbox allows the saw head to be rotated 90 degrees to facilitate felling.
- The handles are brought up, just like, for example, on the "horned" Huskvarna. " This greatly facilitates the work in deep snow and saved the fellers’ backs.
- Also "Ural" is equipped with a chain lubrication system, but there was no such system at Druzhba.
- "Ural" was equipped with a hydraulic wedge. This is a device for stumping cut trees in the right direction.
Domestic chainsaws of the times of the USSR had another significant difference from modern chainsaws. This is a need to run in! If any modern saw does not require running-in as such, the only thing that is recommended is not to work at full speed (for more information about running-in modern chainsaws, read HERE), then Ural and Druzhba had to go through it before work.
Before proceeding with the adjustment, you should make sure that:
- Engine runs smoothly, chain does not move.
- No strong smoke.
The adjustment algorithm is as follows:
- The Ural saw engine starts up and warms up a little. Screw # 3 sets the minimum speed so that the chain stays in place. If the mixture is too rich (heavy smoke is coming out of the exhaust pipe), then screw No. 1 should be slightly tightened. This will reduce smokiness and increase rpm.
- Then it is necessary to return all settings to the level of minimum and stable rpm. This is done by partially unscrewing screw No. 3.
- The next step is to test the engine for throttle response. If, after pressing the throttle lever firmly, the revolutions go up quickly, then everything has been done correctly, and screw No. 3 must be securely fixed in this position.
In the case when the engine stops working or revs are gained slowly, screw No. 1 should be slightly unscrewed. In order to increase the speed, screw # 3 is slightly tightened. After the Ural saw engine is re-tested for throttle response.
Setting the maximum power
Power adjustment on the Ural 2 Electron chainsaw is carried out only after the running-in period has expired (it is 25 hours of operation) and after setting the idle speed.
Incomplete screwing in the screw means more air and less fuel. When the screw is unscrewed, everything happens the other way around, that is, the combustible mixture is enriched. The most preferred position of the screws can be determined exclusively by experiment.
In the process of tuning the Ural carburetor, you must remember the following principles of the correct operation of the chainsaw:
- The engine should always have good cutting performance and the smoke should be moderate.
- The engine should always have excellent throttle response. over, in the process of cutting wood, the chain should not stop, the saw should overheat, and the engine should automatically slow down.
If there was a complete misalignment of the carburetor and the engine stopped starting, it is recommended to perform the following actions:
- Screw No. 1 is fully turned up to the stop, and then turned out one turn, no more.
- Screw # 2 is turned to the limit, and then turned out half a turn.
This will allow you to return the adjusting screws to their original position, and then correctly adjust the carburetor of the Ural chainsaw according to the standards described above.
When the carburetor needs tuning
All new Ural 2 Electron chainsaws supplied by the manufacturer have already passed the standard carburetor adjustment at the factory. However, for the correct running-in of the tool, it will be useful to purposefully lower the engine speed, and then make a fine adjustment. This process allows the engine to perform as efficiently as possible.
In addition, after a certain period, the carburetor settings of the Ural chainsaw go astray. But this is natural, since various difficulties may appear during operation. Symptoms indicating the need to adjust the fuel supply and preparation system include:
- Increased consumption of gasoline. This is caused by oversaturation of the fuel mixture with gasoline.
- Engine stalling or not starting at all. In this case, the reason is excess air and gasoline deficiency.
If everything is in order with the fuel mixture, it means that the carburetor adjustment failure of the Ural chainsaw is caused by mechanical reasons:
- Strong vibration. The protective cap is damaged over time, as a result of which the adjusting screws are arbitrarily displaced.
- Blockage. The use of low-quality fuel, damage to the filter element, the appearance of scale. all this contributes to the appearance of blockages. Complete disassembly, cleaning of the entire system and re-configuration is essential.
- Piston and cylinder wear. If the problem lies in the worn out piston part of the engine, then adjusting the carburetor will only help for a while.
How to adjust the carburetor on the Ural 2 Electron chainsaw
The Ural 2 Electron chainsaw has long established itself as an excellent workhorse with high performance, ease of repair and adequate cost. Almost the only thing that can happen to this tool in the process of competent operation is the lost carburetor settings.
Despite its high reliability, the carburetor of the Ural 2 Electron chainsaw (KMP-100U) may fail. As a rule, such problems are caused by untimely maintenance and neglect of the instrument. For information on how to correctly identify the cause of the malfunction and eliminate it yourself, see.
How the carburetor works on the Ural chainsaw
The design of the carburetor cannot be called complex, which is definitely an advantage of the Ural 2 Electron chainsaws. The main units responsible for the performance of the carburetor include:
- A float chamber made in the form of a reservoir. This element is used to keep the fuel level at an optimal level before mixing with air.
- The channels through which the fuel mixture flows. From the float chamber, the fuel is initially transported to the nozzle, and then enters the sprayer.
- The diffuser, which is a constricted tube. With the help of this element, the rate of entry of air masses is increased to obtain a high-quality fuel mixture.
- A special tube that resembles an aerodynamic structure. This is the main element of the carburetor through which air masses pass. This tube is equipped with a special damper that regulates the amount of air supplied.
How to adjust the carburetor on a Ural chainsaw
Adjustment of the KMP-100U is simple and accessible to every user. The carburetor has two adjusting screws (analogs of the H and L screws on some modern imported chainsaws) for adjusting the average and maximum speed. They are accessible from the outside, no need to disassemble the case for adjustment.
Above you can see 2 screws with springs, these are the adjusting screws
Adjustment of the carburetor of the Ural chainsaw is carried out on a warm engine. Initial tuning should be carried out on a warm, but muffled engine.
- Both screws can be screwed in all the way, but without excessive force. Screws have sharp, fine points that can deform if overtightened.
- Then the first screw, which is closer to the cylinder, is unscrewed by 1 turn. The second screw is unscrewed by 0.5 turns.
- They start the chainsaw, give full speed. In case of a drop in revolutions, the screws can be unscrewed by another 1/3 or 1/4 turn, listening to the engine’s operation and finding the optimal mode.
It is impossible to know the exact number of revolutions. On each chainsaw, this is individual, depending on the characteristics of the carburetor, the state of the piston system, the quality of the fuel, the temperature outside, etc.
To adjust, it is enough to remove the cover, there is no need to remove the carburetor itself from the chainsaw
Lack of tightness
Other problems with the KMP-100U carburetor are loss of tightness. The gaskets between the carburetor and the engine body, and between the parts of the carburetor, must not suck in air during operation and leak fuel when the engine is turned off.
The gaskets can deteriorate for the same reasons as the membrane, that is, dry out, become fragile from time to time.
Idle speed adjustment
The idle speed of the carburetor on the Ural chainsaw is regulated by a screw located on the gas handle. Its rotation changes the position of the throttle valve (opens it slightly) and, as a result, the idling parameters change.
This shows the maintenance of the KMP-100U, and at the end. a simple and understandable adjustment algorithm.
Ural chainsaw carburetor: device, adjustment, repair, revision
All Ural chainsaws were equipped with standard KMP-100 carburetors and its modifications with minor changes. And it was the only carburetor for chainsaws produced in the USSR. Later, with the advent of the newest and last in the USSR model Ural 2t Electron, the KMP-100U carburetor began to be used. And he was the only one for chainsaws produced in the USSR, which stood on Druzhba gasoline chain saws.
Device and principle of operation
The carburetor of the Ural KMP-100U chainsaw is of a membrane type. It does not have a float chamber and a floating float with a needle that cuts off the fuel flow as the chamber fills like older carburetors. This gives the advantage that the Ural 2t Electron chainsaw engine can work in any position, even upside down. The float carburetor cannot operate in an inverted position.
The system of the KMP-100U carburetor can be considered complex, because it must ensure the operation of the engine in three modes:
- Maximum RPM.
For each mode, special channels for the supply of fuel, air and the position of the dampers.
The appearance of the new KMP-100U carburetor used on the Ural 2T Electron chainsaw
When starting a cold engine, the conditions for the formation of a working air-fuel mixture in the combustion chamber are very unfavorable for the following reasons:
- Low crankshaft revolutions with a manual jerk of the starter, weak compression of the fuel mixture in the combustion chamber;
- Some of the fuel is lost on the cylinder walls;
- Low temperature makes ignition difficult.
Therefore, to facilitate starting, the supply of a rich mixture is required. more gasoline, less air. The air supply flap from the air filter in the cold start mode is closed, and the gas supply is increased due to pumping (suction) with a primer.
After starting the engine, a vacuum is created in the combustion chamber during the piston stroke, so the fuel mixture from the carburetor begins to be sucked in there. air is required for oxygen supply and complete fuel burnout. Air damper opens.
When the throttle is pressed, the throttle valve opens fully, gasoline and air flow in full flow, the engine runs at full speed.
The flow of gasoline at this moment is regulated only by the calibrated orifice of the jet in the carburetor.
What other carburetors were put on the Ural 2t Electron chainsaw
On the Ural 2t Electron chainsaw, carburetors from other two-stroke engines with the following engine parameters were often installed, and are being installed today:
- Power 5.5 HP.
- Combustion chamber volume 90.4 cc,
- Piston diameter 55 mm.
Sometimes carburetors were installed from much more powerful engines. For example, from motorcycles "Minsk", "Voskhod". True, there is a drawback, the supply of the fuel-air mixture significantly increases. It was lowered by adjusting the screws. The engine was running, but the fuel consumption was significant.
Determining the need to adjust the carburetor on a chainsaw
Before you start adjusting the carburetor on a chainsaw, you need to make sure that it is generally required. It would seem an absurd phrase. However, in 90% of cases, when an inexperienced craftsman considers such an action necessary, the unstable operation of the instrument is associated with other reasons, including:
- Problems in fuel lines and filter. blockages, depressurization;
- Exhaust system malfunction;
- Clogged or damaged air filter;
- Unstable operation of the ignition system;
- Violation of the tightness of the engine crankcase.
Only if these problems are excluded, and the engine is unstable, it is safe to say that carburetor adjustment is required.
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Features of adjusting carburetors of chainsaws of popular brands with their own hands
Although at first glance, all carburettors are the same, the adjustment of this unit may differ depending on the brand of the tool. Differences may be subtle, but they are and are worth mentioning.
How to adjust the carburetor on chainsaws
To understand how to properly adjust the carburetor on a chainsaw, you need to see it, and therefore we invite the reader to pay attention to the example below.
To make the adjustment, you only need a slotted screwdriver, however, it will not be possible to perfectly fine-tune the carburetor without a tachometer (of course, if the person is not a minder or a professional driver with experience). Now let’s try to understand how to adjust the carburetor in a given situation.
Features of DIY adjustment of the carburetor of the Stihl 180 chainsaw
The Stihl 180 chainsaw carburetor is quite interesting. Its peculiarity is that two of the three usual adjusting screws are absent on it. And therefore, the adjustment of the carburetor of the Stihl 180 chainsaw is reduced to an elementary adjustment of the idle speed with the help of a single LD screw. But the same cannot be said about another model of the Stihl 250 brand. Here, the assembly is almost familiar, with three screws. The only difference is that the idle speed when adjusting the Stihl 250 carburetor is adjusted with screw H, not T.
How to set up a chainsaw carburetor if it won’t start at all
Quite a common problem in cases when a “master” from the “I know everything” series tries to get into the settings with hands that do not grow from the shoulders. In such a case, there are standard screw positions from which you can "dance" further. First, you need to completely tighten both screws (do not overdo it). Then unscrew:
- Screw L. one turn;
- Screw H. one and a half turn.
With regard to the idle screw, the throttle must first be completely closed (screw T removed). After that, it must be cranked one and a half turns clockwise and try to start the engine. If it did not work out, it is gradually added by a quarter of a turn before starting. When the engine starts to work, the position of the idle screw is adjusted so that the internal combustion engine does not stall, but the chain is still in place.
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The nuances of adjusting the carburetor of chainsaws, brand "Ural"
The adjustment is made according to the following algorithm. First, idle speed (idle screw) is set to keep the chain static. If there is heavy smoke from the exhaust pipe, tighten the full throttle screw slightly. At the same time, there will be less smoke, and the speed will increase. So, by alternately setting the screws, you can achieve an optimal result.
Then you should sharply press the gas lever. If the revs went up quickly, then everything is normal, you can fix the idle screw. If they do not grow dynamically enough, it is worth unscrewing the full throttle screw a little. And after running in, you can already adjust the maximum power.
By the way, a similar carburetor is installed on the Taiga chainsaws, which means that the adjustment will be identical.