Engines UD 25 and UD 15 were produced many years ago, but are still used by amateurs of such equipment. Despite the fact that they are more than a dozen years old, they serve faithfully to their owners. Such engines were used to drive electrical power units and mobile power plants, various agricultural, construction and road machines, including MTZ walk-behind tractors, often used on homemade mini tractors.
Stationary subcompact engines UD-15, UD-25 and their modifications are designed on the basis of the MEMZ-966 (965) engine of the Zaporozhets automobile. The UD-15 engine is single-cylinder, and the UD-25 is two-cylinder. Both UD models are made according to the same design scheme and are maximally unified.
Listening to the engine during its operation allows you to determine the state of the main parts in the places of their connections (landings). The knock of the piston, which occurs when the pistons are heavily worn, is well audible on an unheated engine on the left side of the cylinder. The knock of the piston pin, which occurs when there is a large gap between the pin and the connecting rod or the pin and the piston, is heard in the upper part of the cylinder head, and, with a sharp increase in revolutions, the knock increases.
The knock of the connecting rod, which occurs when there is a large clearance in the connecting rod bearing, is best heard at the top of the crankcase near the cylinder. The noise of rolling bearings, which occurs during their wear, is heard near their installation sites. Gear noise occurs when the meshing clearance is increased. The knock of the rocker arms, which occurs when the clearance between the valve and the rocker arm is increased, is heard in the upper part of the head.
Also on these motoblocks the SK 6 and SK 12 engines were used. Here is the user's manual for these engines.
UD 15 engines were installed on the MTZ walk-behind tractor. Detailed information on MTZ 05, MTZ 06/12 walk-behind tractors is posted on the corresponding pages of the site.
The K-16M (K45M) carburetor is installed on the UD-15, UD-25 engines. The carburetor device is shown in fig. 10, 1 1. Carburetor 3 (Fig. 10) is adapted to work with a centrifugal regulator: throttle valve 6 is controlled by a lever with a sphere, which is acted upon by the regulator lever 7. For manual control of the throttle, there is a leash in the upper part 2. Air damper 9 is operated manually.
The carburetor provides the ability (if necessary) to adjust the engine at low idle speed. The adjustment is carried out by the stop adjusting screw 4 located on the throttle lever in the upper part. Low idle speed should not exceed 1600 rpm. Adjustment of the mixture quality at idle speed is made with screw 5.
Fuel is supplied to the carburetor by a diaphragm fuel pump 10 from a separate gas tank not connected to the engine. The fuel pump is operated by a cam located on the camshaft. The design provides a lever for the manual drive of the fuel pump.
Air enters the carburetor through an inertial oil filter 1. The fuel level in the float chamber is maintained constant (19 ± 2 mm) by means of a float 1 (Fig. 11) and a shut-off needle 2. With the float lowered, the channel through which fuel comes from the gasoline pump, open. The fuel, filling the float chamber, raises the float, which closes the fuel supply channel with a shut-off needle. There is a float sink in the float chamber cover. The carburetor float chamber is not balanced.The idle system is fed with fuel up to the main jet.
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Everything for the modernization and repair of the engine
This engine was installed on the MTZ-05 walk-behind tractor. The walk-behind tractor has been in operation since 1990.
Since my tractor is assembled and adapted for the UD2 engine, I had to accept this ICE with all its whims. And he is capricious as a baby. And so the work plan:
We proceed to reduce the combustion chamber. We mill the engine heads by 2mm
Further, there is a full flow-through lubrication system.
further magneto, redone very easily. From the old magneto remained the body, cams, slider and ignition timing. Added babin.
I'll wait with the starter, because there is no need for it yet. The engine starts with half a turn.
3.3. GAS DISTRIBUTION MECHANISMS FOR MINI TRACTOR ENGINES
Gas distribution mechanism of the UD-15 engine
To ensure the necessary valve movements, the large rocker arms are 1.3-1.5 times longer than the short ones and end with hardened cylindrical surfaces. In the short arms, there are adjusting screws with a ball head and a locknut 7, designed to adjust the gap between the large arm of the rocker arm and the valve. The rocker arms are located under the head cover 8, where the rods of the pushers 10 enter with their upper tips 9. The rods are hollow for relief, and the tips of the pushers are pressed into the rods and have spherical sockets: the upper ones are for the heads of the adjusting screws, the lower ones are for the pusher rods. The second rod has lugs with through holes through which oil is supplied.
To fix the rod covers in the cylinder head, a second spring 11 is installed between the rod thrust ring and the pusher bushing 12. The pusher bushings are pressed into the crankcase and have holes for oil supply. The correctness of the insertion is controlled by the marks on the sleeve. Pushers 13 are designed to transfer movement from the cams of the camshaft 14 to the rods. The pushers are mushroom-shaped with a flat head. There is an oil hole in the pusher rod. The pusher heads slide along the generatrix of the cams of the camshaft 14, which, in addition, has a fuel pump drive cam. The camshaft is driven by a gear 15 meshing with the crankshaft timing gear. In the engine crankcase, the camshaft is mounted on sleeve bearings 16 made of bronze tape. The gas distribution phases provided by the mechanism are given in table. 3.1, which also presents similar data for the ZID-3 engine.
Workshop address: Phones:
We always have original high-quality spare parts and consumables for UD 15 and UD 25 engines in our warehouse. Also in our workshop you can purchase spare parts for repairs and consumables for servicing all kinds of garden equipment: walk-behind tractors, motor-cultivators, mini tractors, chainsaws, brushcutters, cutters, etc. We deliver spare parts to the client, we send them by mail. We carry out repair and maintenance of motoblocks and mini-tractors of any complexity in the workshop and on the road.
The catalog contains only a part of spare parts, any information regarding the details you need and prices can be specified by phone: +375 29 6741674, +375 17 5123712.
Cylinder head, UD 25 engine.
Muffler, engine UD 25.
Ratchet nut engine UD 15, UD 25.
Oil pump, engine UD 15, UD 25.
Air filter, engine UD 15, UD 25.
Details of the cylinder-piston group:
inserts, all repair sizes, standard, overhaul, engine UD 15, UD 25;
piston, rings, standard, repair, engine UD 15, UD 25;
piston fingers, engine UD 15, UD 25.
Camshaft gear, engine UD 15, UD 25.
Valve cover, engine UD 15.
Carburetor K45 M3, engine UD 15, UD 25.
Lubricating washer, engine crankshaft UD 15, UD 25.
Crankshaft thrust washer, engine UD 15, UD 25.
Ratchet gear, engine UD 15, UD 25.
Ring spacer for the ZAZ cylinder, engine UD 15, UD 25.
Centrifuge seal, engine UD 15, UD 25.
Magneto M 124 B, UD 15 engine.
Magneto M 137, engine UD 15.
Contacts for M 137 magneto, UD 15 engine.
Bearings, cuffs, engine UD 15, UD 25.
Speed controller, engine UD 15, UD 25.
Kickstarter spring, engine UD 15, UD 25.
Spark plugs A 11, engine UD 15, UD 25.
Drive drum hub, engine UD 15, UD 25.
Fuel line from the fuel pump to the carburetor, from the fuel tank to the fuel pump, engine UD 15, UD 25.
Pulley for starting, engine UD 15, UD 25.
ChSUP "Motoblok-master", a / g Ozertso, st. Green 18.
At the end of the sixties of the last century, the Ulyanovsk Motor Plant produced two-cylinder power units with excellent technical characteristics. The stationary UD 25 four-stroke carburetor engine is one of them. At one time it was developed on the basis of the MEMZ-965 engine used in small cars of the famous Zaporozhets brand. The UD 25 engine is often found in home-made agricultural machines, construction mechanisms, etc.
This unit is designed to be installed on the following technical equipment:
at mobile power plants;
small walk-behind tractors, tractors, motor-cultivators and other agricultural machines;
low power vehicles;
walk-behind tractors;
road equipment, etc.
Photo of a walk-behind tractor with an UD 25 engine:
Technical characteristics of the UD 25 engine:
Interesting: Simultaneously with the UD 25 unit, the UD 15 engine was produced at the Ulyanovsk Motor Plant, which has similar characteristics. The main difference between these models was the number of working cylinders. The UD-25 has two cylinders, the UD-15 has one.
The power unit is reliable, durable, easy to operate, and easy to maintain. A distinctive feature of this motor is its compactness, while it develops a solid power, thanks to which it is very popular among numerous gardeners, farmers and other land owners.
The UD 25 four-stroke engine is equipped with an air cooling system. There is no need to change the coolant, however, during operation, it is necessary to monitor the temperature of the engine in order to prevent it from overheating. In the absence of good ventilation, it is not recommended to run this motor indoors.
In comparison with similar stationary units, this engine does not differ in increased demands on the quality of service. The main care of the UD-25 engine consists in performing the following activities:
Purification of the elements of the power supply system.
Cleaning the air filter.
Partial or complete replacement of engine oil.
Repair and restoration work is available for self-fulfillment in a garage. This significantly reduces the material costs associated with the operation of this engine.
Regulations for the maintenance of the UD-26:
Violation of the terms of service will lead to a change in the operational and technical characteristics of the engine for the worse. It is noticed that compared to modern engines, oil and other consumables have to be changed more often. This is due to the use of lubricants and gasoline of obviously poor quality.
During the operation of this power unit, the main malfunctions are noted:
Extraneous noise with a characteristic metallic sound.
The motor is unstable, smokes.
Decrease in power.
Oil leaks.
To eliminate noise during engine operation, it is recommended to adjust the valve clearances of the intake system.
To reduce the amount of exhaust gases and restore engine operation after a long run, you will have to put the car for a major overhaul. In this case, the compression, as well as the oil scraper rings and caps must be replaced.
With a deterioration in the performance of the internal combustion engine. It is recommended to check the quality of the carburetor, which is responsible for the formation and supply of air-fuel mixtures to the cylinders. This will require diagnostics of the power supply system with the obligatory disassembly of the carburetor.
If engine oil seeping is noticed, the reasons should be looked for in the violation of the integrity of the valve cover gasket. For this, the cylinder head head is removed, the leaking gasket is removed and a new sealing element is installed instead. It is not recommended to postpone this event until later, since the engine will not be able to work for a long time at a low oil level.
Given the relatively small margin of safety of the working units and parts of this unit, it is considered impractical to modernize it. However, the owners of the UD 25 engine often use the possibilities to improve some performance characteristics:
Replace attachments that reduce gasoline consumption and restore engine stability.
The standard carburetor is removed and a Chinese-made analog removed from scooters is installed instead.
With the help of such tuning, fuel consumption is significantly reduced while maintaining power and torque indicators.
Experienced craftsmen manage to increase the power to 15 liters. With. by reconfiguring the carburetor. As a result of the corresponding improvements, a richer air-fuel mixture enters the cylinders.
Depending on the scope of use and the UD-25 engine, it was aggregated with various attachment modules. At the same time, the design and principle of operation of the motor underwent some changes. Customers could choose any modification based on their individual needs. The models included various components:
carburetors;
fuel pumps;
attachments for performing various works (agricultural, construction, road, forestry, etc.).
Despite the fact that the UD-25 engine has long been out of production, many mechanisms continue to work with its participation. They can be found in devices such as mini tractors, small power plants, walk-behind tractors, which are actively working and are beneficial in rural areas and other areas remote from the centers of civilization.
Stationary grinding engines. UD-15, UD-25 and their modifications. technical description and operating instructions
1 Stationary milling engines UD-15, UD-25 and their modifications technical description and operating instructions ATTENTION! This publication sets out the design features of the engines, the requirements for operation and maintenance of them. Timely and accurate compliance with the rules of care and operation will ensure trouble-free operation of the engines. This publication cannot serve as a textbook for the course of engines, therefore, persons authorized to operate UD engines must have theoretical and practical knowledge of internal combustion engines and their operation. Due to the improvement of the design, non-fundamental deviations in the use of the engine from the text and illustrations of this publication are possible, which do not affect the quality of operation and maintenance of the engines. USSR V / O ENERGOMASHEXPORT MOSCOW 4
Fig. 3 1. Longitudinal section of the UD-15 engine: 1 - flywheel casing; 2 - ratchet nut; 3 - tube for supplying lubricant; 4 - oil filter cover; 5 - flywheel fan; 6 - cylinder cover; 7 - muffler; 8 - crankshaft; 9 nut М20; 10 - cuff of the crankshaft 7 Fig. 2. Longitudinal section of the UD-25 8 engine
6 The head of the UD-25 engine is made common for both cylinders, the head of the UD-T5 engine is two-cylinder in the form of a half compartment. COOLING The cooling system (fig. 8) removes heat from the cylinder walls and head. The engines have a forced air cooling system. The cooling system includes: flywheel-fan 4, flywheel casing 5, cylinder casing 2, air outlet casing 3. The degree of engine cooling is adjusted by opening or closing louvers 1 in the casing of the flywheel fan. Rice. 6. Gas distribution system: 1 - camshaft gear; 2 - a camshaft; 3- pusher bushing; 4 - valve; 5 - barbell; 6 - rocker; 7 - cylinder head; 8 - pusher 13 14
8 The carburetor provides the ability (if necessary) to adjust the engine operation at low idle speed. The adjustment is carried out by the stop adjusting screw 4 located on the throttle lever in the upper part. Low idle speed should not exceed 1600 rpm. Adjustment of the mixture quality at idle speed is carried out with screw 5. Fig. 10. Power system: 1 air filter; 2 leash; 3 carburetor; 4 adjusting screw; 5 screw idle; 6 throttle valve; 7 regulator lever; 8 carburetor throttle lever; 9 air damper; 10 fuel pump Fig. 9. Regulator: 1 - nut М8; 2 - clutch leading magneto; 3 - gear wheel of the regulator; 4 - ball bearing 203; 5 - ball bearing 303; 6 - carburetor throttle valve; 7- regulator roller; 8 - cam; 9 - Balancers; 10 - pushers; 11- lever; 12 - regulator spring; 13 - spring pin of the regulator Fuel is supplied to the carburetor by a diaphragm fuel pump 10 from a separate gas tank not connected to the engine. The fuel pump is operated by a cam located on the camshaft. The design provides a lever for the manual drive of the fuel pump
26 To clean the starting accelerator it is necessary to remove it, rinse it thoroughly in clean gasoline (without disassembly) and dry it or blow it out with compressed air. Then immerse in a mixture of 50% turbine oil L ”GOST with vaseline oil in accordance with GOST and in this way set the lubricated starting accelerator on the magneto. After 1000 hours of operation, clean the crankshaft cavities from deposits, for which: drain the oil; separate the pallet; turn the crankshaft so that the counterweights are at the top; unscrew the plug. Assembly is carried out in the reverse order of disassembly. Attention! When installing the flywheel-fan on the crankshaft, install the key as shown in Fig.
Since my tractor is assembled and adapted for the UD2 engine, I had to accept this ICE with all its whims. And he is capricious as a baby. And so the work plan:
We proceed to reduce the combustion chamber. We mill the engine heads by 2mm
Further, there is a full flow-through lubrication system.
further magneto, redone very easily. From the old magneto remained the body, cams, slider and ignition timing. Added babin.
I'll wait with the starter, because there is no need for it yet. The engine starts with half a turn.
3.3. GAS DISTRIBUTION MECHANISMS FOR MINI TRACTOR ENGINES
Gas distribution mechanism of the UD-15 engine
To ensure the necessary valve movements, the large rocker arms are 1.3-1.5 times longer than the short ones and end with hardened cylindrical surfaces. In the short arms, there are adjusting screws with a ball head and a locknut 7, designed to adjust the gap between the large arm of the rocker arm and the valve. The rocker arms are located under the head cover 8, where the rods of the pushers 10 enter with their upper tips 9. The rods are hollow for relief, and the tips of the pushers are pressed into the rods and have spherical sockets: the upper ones are for the heads of the adjusting screws, the lower ones are for the pusher rods. The second rod has lugs with through holes through which oil is supplied.
To fix the rod covers in the cylinder head, a second spring 11 is installed between the rod thrust ring and the pusher bushing 12. The pusher bushings are pressed into the crankcase and have holes for oil supply. The correctness of the insertion is controlled by the marks on the sleeve. Pushers 13 are designed to transfer movement from the cams of the camshaft 14 to the rods. The pushers are mushroom-shaped with a flat head. There is an oil hole in the pusher rod. The pusher heads slide along the generatrix of the cams of the camshaft 14, which, in addition, has a fuel pump drive cam. The camshaft is driven by a gear 15 meshing with the crankshaft timing gear. In the engine crankcase, the camshaft is mounted on sleeve bearings 16 made of bronze tape. The gas distribution phases provided by the mechanism are given in table. 3.1, which also presents similar data for the ZID-3 engine.
MTZ walk-behind tractor motor: gasoline or diesel?
The tiller does not include many parts. Each of them carries a certain burden on itself, and its absence nullifies the whole concept. walk-behind tractor.
The engine, like all cars, takes pride of place in the walk-behind tractor. Using the energy of combustible fuel, all internal components and mechanisms move. Thus, the fuel entering the combustion chamber is ignited by a candle. Fuel, burning, turns into gas, which presses on the piston. The latter is associated with the crankshaft, which provides torque to external mechanisms. Fuel supply and timing is carried out using valves, each of which can have multiple cylinders.
The resulting torque in the motor unit is used for two purposes. One of them is the rotation of the wheels and the movement of the entire block. Second. rotating attachment parts. Here, the power transmission is carried out by the transmission and the power take-off shaft.
Motoblock engines are required to provide clear and reliable functionality of the entire unit. They should be compact, economical, lightweight, relatively powerful and have a long motor resource. Since they are intended for private use, price matters a lot.
These requirements are met by small, single-cylinder, four-stroke gasoline and diesel engines.Their capacity ranges from 5 to 15 liters. With. This fully satisfies the ability of one person to operate and work with the motor unit.
There is always controversy around the use of the engine on walk-behind tractors. Both devices have their own advantages and disadvantages. Carbureted engines usually have an air-cooled system that allows you to gain somewhat in complexity and size. Liquid cooling is often used in diesel units.
The gasoline engine has a smaller size and weight, which greatly exalts them over diesel ones. It doesn't take much wisdom to get started, and the beginning itself is almost instantaneous. Another advantage of the gasoline unit. relatively low noise level. All these qualities start to disappear when it comes to fuel consumption. For comparison, a conventional diesel with a capacity of 9 liters. from. burns 0.9 liters per hour in medium mode. A gasoline engine, which is often installed on a domestic 5-liter walk-behind tractor. with., consumes twice as much at the same loads. Even after diesel is nearly equal to gasoline, diesel remains much more fuel efficient.
Diesel power units remain technically more reliable, but they are not capable of developing the same speed as gasoline ones.
This debate can be continued endlessly, and still there will be fans of those and other divisions who will say that they have found the best option.
During the entire production period of engine blocks, the Minsk Tractor Plant has mastered the entire line of devices for this purpose. This included MTZ with markings: 05, 06, 08 and 12. Later Belarus-09N was added to them. The numbers characterize the power of the units in horsepower (0 is not taken into account).
VIDEO
Repair UD engine —15 after 28 years of operation on walk-behind tractor MTZ-05. P.S. After editing the entire video, I found it.
VIDEO
UD —15 on the walk-behind tractor MB-2, in 2nd gear engine does not pull :(, by itself it is low-speed, you give a little gas.
One of the engines for domestic motoblocks was the UD-2, which was developed in Ulyanovsk. It is a two-cylinder, four-stroke gasoline engine. The total volume is 0.6 cubic meters. cm and a capacity of 8 liters. from. The engine develops 3000 rpm. The dry weight is 72 kg.
Next model. UD-4. This engine has 4 cylinders and a total displacement of 1220 cc. see its characteristics. the lower position of the valves.
Motoblock MTZ-05 received the UD-15 gasoline engine. It is an air-cooled, four-stroke, single-cylinder unit. The working volume is 245 USD. its capacity is 5 liters. from. Engine capable of delivering 3000 rpm and weighs 41 kg. This engine is most often used on domestically produced walk-behind tractors and household items. It's easy to maintain and fairly easy to purchase parts for.
Unlike the previous model, the UD-25 contains two cylinders. The working volume has reached 490 cubic meters. cm, which made it possible to increase productivity up to 8-10 liters. from. The device weighs 52 kg.
Motoblocks MTZ-09N are equipped with foreign-made gasoline units. This is the Honda GX270, its Chinese counterpart. Lifan LF177 and Kipor KG270. The Japanese engine runs on gasoline. Has 1 cylinder. The working volume is 269 cubic meters. cm, which allows you to get 9 liters. from. power.
Not so long ago, MTZ tractors received a diesel unit. This was done thanks to the joint efforts of Belarus and China. The model received the DD-12 marking. The engine has a four-stroke circuit and includes 2 cylinders. The device has a capacity of 16 liters. from. Starting is done using an electric starter. The kit includes a twelve-volt generator.
As with any technique, the motors of the motor units are subject to malfunctions. Despite the simplicity of assemblies, there can be many reasons: from factory failure and misuse to natural wear and tear of parts, since motors must be constantly used.
Malfunctions of engine blocks can be divided into three types:
Electrical part.
Fuel system.
Mechanics.
The most common electrical malfunction is the lack of starting. Usually the candle is the cause. This could be the culprit for carbon build-up, poor installation, or complete failure. More often than not, a simple replacement solves all problems. The object of diagnostics should also be wiring and magneto.
The lack of starting and abnormal operation of the engine are directly related to the fuel. The test is started by checking the fuel in the tank. Then the fuel line is checked. Particular attention is paid to the carburetor. The best way. clean this part completely and check the free movement of all moving parts.
The mechanics of the motor units will fail in the following cases:
Unstable work. wear of piston rings, formation of deposits on valves;
Black smoke when exhausted. Clogged air filter or worn rings
Overheating and falling speed. low oil level;
Motoblok comes off during launch. the key on the flywheel collapses, inconsistencies in the gears of the knees and camshafts (incorrect assembly);
The crankshaft does not work when starting. the three-point clutch is broken;
The engine is constantly revving up. loosening of the connection between the adjuster lever and the traction lever.
Video (click to play).
The list goes on as the problem can manifest itself in almost every detail. Nevertheless, a person who is at least familiar with the technology easily understands all the features and nuances regarding the power unit of domestic motor blocks.
