How To Disassemble The Gearbox Of The Neva Mb 2 Walk-Behind Tractor

Instructions for assembly, operation and repair of the NEVA MB-2 walk-behind tractor The manual for the Neva MB-2 walk-behind tractor will help you to recognize the device. The gearbox mainly suffers from breakdowns. A description of the repair will help.

Walk-behind tractor device

Today it will not be a secret for anyone that the MB 2 unit is the most popular equipment among lovers of rural labor and is in great demand.. The tiller of this mowing line is produced in several modifications, differing from each other by the brand of the engine. These include:

A model with a 2K index, equipped with a motor from a domestic manufacturer with a long service life and a rather low price;
Neva with the designation 2B mini tractor is equipped with an imported engine, mainly from Briggs and Stratton;
Modification 2C, equipped with professional elements for processing earth balls from the manufacturer EX Robin Subaru.

The motor is selected based on the amount of work or the size of the land plot that the walk-behind tractor will handle. Usually, this unit is adapted to work without much effort on 10 15 acres of land. For operation on large areas, you need to buy MB 2 with a 9 horsepower engine.

The design of a mini tractor brand Neva consists of the following main components:

Gear chain type reducer. This element is in a special case made of aluminum alloy. The main purpose of the gearbox is to provide high-speed modes. The unit has 4 forward and 2 reverse gears. The maximum speed is 12 km / h, which makes it an excellent carrier of goods during operation.
A motor with a starter to start the mini tractor into operation.
Supporting frame construction. It has a special device from the front to the back for attaching and installing attachments for the performance of work.
Steering device. It has special levers for controlling the tractor during operation.
V-belt transmission. The device acts as a transmission for the clutch assembly and consists of a pulley, a special lever and a V-belt.

It is worth noting that the heaviest modification of the walk-behind tractor weighs 98 kilograms. This indicates the compactness of the unit, thanks to which it can be delivered to its destination in the trunk of a passenger car.

Instructions for assembly, operation and repair of the NEVA MB-2 walk-behind tractor

12.01.2016 123 Views

The motoblock, under the Neva logo, known to the rural worker, belongs to the category of small-sized agricultural machinery manufactured at the Krasny Oktyabr plant in St. Petersburg. In fact, this brand of minitractor for gardeners and amateur gardeners is not new. The Neva was included in mass production in the mid-80s. The motoblock of this brand has become a pioneer in the domestic market of small equipment for rural areas. Throughout this time, to the present day, this model has only been modernized and improved.

Trailer for walk-behind tractor with plow

Characteristics of MB 2 and MB 2K

Neva modification MB 2 with index K is used for processing different types of soil. It is perfect if you want to work on the so-called heavy soils in the form of virgin land. The most surprising thing is that this unit is subject to operation in the winter. For operation during this period of the year it is necessary to use oil of the SAE 10W20 series.

The MB 2 with the K attachment can perform a wide range of agricultural operations, such as plowing the soil, cultivation, planting seeds of potatoes and other crops, hilling, weeding between rows and harvesting. The Neva can perform these manipulations using a wide selection of attachments, as well as those laid down by the resource manufacturer. The technical capabilities of the MB 2 model with the letter K are as follows:

The unit is refueled with gasoline.
Equipped with a domestic-made motor DM 1K. The engine is 4-stroke and has one cylinder.
The power of the device is 7.5 horsepower.
The volume of the motor is 317m3.
The engine starter is of the manual type.
Cooled with air and liquid.
The gasoline capacity is 2.9 liters.
A gear chain reducer is installed.
Fuel consumption at maximum operating mode is 2.8 liters per hour.
The grip when performing cultivation is 160 cm.
The depth of the cultivated soil is 15-25 cm.
The dimensions of the tractor are in this ratio; length is 1740 mm; height 1300 mm; width 650 mm.

The characteristics related to the MB 2 modification can be formulated as follows:

The maximum grip of the working area is 120 cm.
The depth of soil processing is 20 cm.
The cultivation speed is 12 acres in 1 hour.
The fuel capacity is 3.6 liters.
Fuel consumption at maximum operation is approximately 1.6 liters per hour.
4-stroke single-cylinder motor with manual starter.
The components are cooled by an air system.
The equipment is powered by rotation transmitted from a gearbox through a three-groove pulley.

Assembly instructions

Based on practice, the Neva goes on sale assembled. But having bought this car for his backyard, the owner is faced with the issue of adjusting the main units. This allows you to prepare the unit for full operation, making the most of the characteristics.

The most important thing in this process is the adjustment of the engine and the fuel system. As the instructions indicate, the level of gasoline entering the float chamber of the carburetor of the walk-behind tractor must be adjusted using a special reed device. It can be pressed or pressed. This process allows you to properly adjust the operation of the carburetor, on which 90% of the correct operation of the entire motor depends.

In order for the engine to run with minimal interruptions, it is necessary to adjust the valve system. To do this, as the instructions suggest, you need to disassemble the carburetor and unscrew all the screw connections of the upper and lower housing and clean all the elements of the carburetor. After that, you can start adjusting the valves of the walk-behind tractor. First you need to screw the gas adjusting screws all the way to the maximum limit. Then they need to be unscrewed by one and a half turns and start the engine.

[attention type = green] Before adjusting the valve system, the motor must be warmed up for 5 minutes. After that, the throttle lever must be set to the lowest position, the hundred maintains stable rpm. Next, you need to tune the motor to a stable minimum speed, when the engine runs without interruption, that is, steadily.

Operating instructions

In reality, the Neva works perfectly if the following steps are consistently followed:

When installing the cultivating device, the knives should be directed in the direction of travel.
When wheels slip during operation, additional weights must be installed.
It is necessary to monitor the quality and purity of fuel.
When a cold device starts up, it is required to close the air supply using a special valve. When the motor is heated, this element does not need to be closed.
After starting, you need to set the throttle to position XX and warm up the engine for 3 minutes. When the engine is warming up, it is strictly forbidden to set the maximum speed.
Care must be taken not to get oil on the air filter element.

Repair instructions

The Neva, like any other mechanism, can be subject to various technical faults. If they occur, some units are subject to repair, while others are simply replaced. In either situation, you need to have certain skills that will help eliminate the breakdown. This rule especially applies to the gearbox, which is the main mechanism in the machine in question.

Faults in the gear unit include:

Oil leakage along the shaft. It is required to remove the gear cover and replace the lip liner.
When braking the gearbox, the broken chain must be replaced.

In fact, the considered brand of mini tractor does not require great requirements for operation. Due to its simple device, the machine is in demand in our country and abroad. A wide network of service centers helps owners to quickly restore the functionality of nodes at affordable prices.

Probable breakdowns and repair of the gearbox of the Neva MB-2 walk-behind tractor and analogues

Oil flows through the shaft. The cuff is probably worn out. To fix the problem, remove the cover, replace the worn part.

How To Disassemble The Gearbox Of The Neva Mb 2 Walk-Behind Tractor

Failure of the semiaxis decoupling unit. May be caused by failure of any of the drive components. Disassembly, replacement of broken products will be required. If the problem is caused by a misalignment of the drive, then only a change in the cable tension is required.

Unit wedges open circuit. Having untwisted the unit, you need to install a new chain.
No connection. The problem is caused by a damaged pinion-to-block shaft weld. Disassembly of the unit, replacement of the shaft will be required.
The transfer is not recorded. There may be several reasons:
The working qualities of the fork brush have deteriorated, having untwisted the unit, the element should be replaced;

The spring or the unit clamps is out of order make a replacement, make an adjustment;
The settings in the switching device have changed after loosening the board screws, you need to make the first gear, and then tighten the screws.

The described breakdowns and their causes are the most typical and popular. It should be noted that if you cannot eliminate defects with your own hands, then it is better to contact a specialist.

How to choose a motoblock gearbox

It has become much easier to carry out maintenance work today. After all, you don’t have to do everything manually. For the processing of small land plots, small-sized motoblocks are used, and I must say effectively. These devices allow you to cultivate the soil, say, when growing potatoes, to remove leaves with a rake, and snow to dump. In a word, the functionality of motoblocks is amazing. And thanks to their advantageous compactness, using them in small areas turns out to be an effective measure.

Repairs

To repair the gearbox, you will need to disassemble it. But for this, the unit must be cleaned, dirt removed and the oil drained. Next, you need to disassemble and identify defective elements. This is achieved by inspection or mechanical strength testing. Spare parts of the motoblock gearbox must be used new and only original, if there is no desire to risk the performance of the unit.

After assembly, you must not forget to pour oil into the gearbox of the Neva walk-behind tractor. Otherwise, it will lead to its failure.

About device

A gearbox is necessary to transmit the rotational motion of the engine to the wheels and attachments. It determines the gear ratio as well as the direction. We will consider a model that is installed on Neva MB-1 walk-behind tractors. In principle, the design of other manufacturers is very similar, almost identical, so it will become a clear example of how this unit looks and works. Let’s look at the gearbox assembly for the walk-behind tractor.

The device of the gearbox of the walk-behind tractor is organized in such a way that the elements responsible for engaging gears are located at the top of the body. The gearshift lever is capable of five positions.

By pressing the lever, the fork disengages the clutch. Releasing the lever, the fork moves to the starting position. The drive is connected to the right axle shaft, the walk-behind tractor slows down.

Torque is transmitted from a sprocket attached to the input shaft (left or right). When the handle is recessed, the left sprocket engages, a low gear is activated. Top gear starts when the handle is fully extended.

The difference between the design of the Neva MB-1 gearbox from, for example, the Cascade is in the features of the output shaft. In the latter case, it is mounted on ball bearings.

Adequate quality of service long service life

Note that the repair of the motoblock gearbox will not take very long, if you fill it with oil in time, monitor its level, avoid shock loads and carefully operate it. Thus, correct operation is the key to a long service life not only of the gearbox, but also of other elements of the walk-behind tractor.

How to choose a motoblock gearbox

About device

A gearbox is necessary to transmit the rotational motion of the engine to the wheels and attachments. It determines the gear ratio as well as the direction. We will consider a model that is installed on Neva MB-1 walk-behind tractors. In principle, the design of other manufacturers is very similar, almost identical, so it will become a clear example of how this unit looks and works. Let’s look at the gearbox assembly for the walk-behind tractor.

The difference between the design of the Neva MB-1 gearbox from, for example, the Cascade is in the features of the output shaft. In the latter case, it is mounted on ball bearings.

Probable breakdowns and repair of the gearbox of the Neva MB-2 walk-behind tractor and analogues

Oil flows through the shaft. The cuff is probably worn out. To fix the problem, remove the cover, replace the worn part.

Failure of the semiaxis decoupling unit. May be caused by failure of any of the drive components. Disassembly, replacement of broken products will be required. If the problem is caused by a misalignment of the drive, then only a change in the cable tension is required.

Unit wedges open circuit. Having untwisted the unit, you need to install a new chain.
No connection. The problem is caused by a damaged pinion-to-block shaft weld. Disassembly of the unit, replacement of the shaft will be required.
The transfer is not recorded. There may be several reasons:
The working qualities of the fork brush have deteriorated, having untwisted the unit, the element should be replaced;

The spring or the unit clamps is out of order make a replacement, make an adjustment;
The settings in the switching device have changed after loosening the board screws, you need to make the first gear, and then tighten the screws.

The described breakdowns and their causes are the most typical and popular. It should be noted that if you cannot eliminate defects with your own hands, then it is better to contact a specialist.

Repairs

After assembly, do not forget to pour oil into the gearbox of the Neva walk-behind tractor. Otherwise, it will lead to its failure.

Adequate quality of service long service life

Application nuances

In order for the user to have to deal with a breakdown of the walk-behind tractor as rarely as possible, it is required to monitor the operation of not only the engine, but also the gearbox. Experts give their advice on what basic requirements must be observed during operation.

Features:

A gear-chain unit is installed in the design of the walk-behind tractor, the main task of which is the transmission of rotational motion, and therefore, the change in the rotational speed of the cutters. It is thanks to the gearbox from the driven pulley that the mechanical action is transmitted to the wheels of the equipment, whereby the speed and direction change.

There is oil inside the housing, which is necessary to ensure the operation of the gearbox. The element is enclosed in a robust sealed housing. Its kinematic diagram consists of a chain and two stars located in opposite directions. The lower one is called the driven one, since it stands on the shaft and drives the entire system of the walk-behind tractor.

Composition

The gearbox of the walk-behind tractor includes the following important parts:

Screws;
Bearings;
Axles;
Asterisks;
Body;
Bushings;
Shift levers;
Gear wheels;
Shaft;
Clutch;
Half-shafts;
Pay;
Spring.

These are not all the elements that are involved in the design of the gearbox, but they are the main ones. Failure of one of them leads to loss of performance and subsequent repairs.

Compared with a worm gear, the gear-chain has more reliability. It is convenient and easy to operate, can support the reverse function. As a rule, this is a collapsible design, where all the elements are connected to each other by bolts, thanks to which you can inspect the condition of the chains and gears if necessary. Such gearboxes are installed on large walk-behind tractors, which need a strong and reliable unit to transmit power to the wheels and cutters.

Reducer of the Neva MB-2 walk-behind tractor: diagram and device, purpose and operating rules

Features:
Composition
Application nuances
Possible breakdowns

The gearbox is an indispensable component of any technique where an engine is used, since without it, the transmission of rotary motion is impossible. Structurally, this element in the Neva-MB-2 walk-behind tractors is similar to the parts used in other equipment, but in order to learn more about it, it is necessary to study the issue in more detail.

Possible breakdowns

It is worth saying that the gearbox from the Neva-MB-2 walk-behind tractor is repaired quickly and easily. This is possible due to the fact that you can always find spare parts for it on the market. Such a need arises when the following symptoms appear:

Oil begins to appear on the output shaft;
The chain is jammed;
No kinematic connection;
No gear shifting.

In all these cases, it is required to disassemble and inspect the gearbox. If oil leaks, the problem can be eliminated by simply replacing the cuff, which may lose its original qualities over time. Jamming is always associated with a broken chain, so this problem can only be eliminated by a complete replacement. If this element is intact, but there is no kinematic connection, you should pay attention to the sprockets present in the design. One of them could break off.

In the absence of a gear change, a cracker is inspected, which can be destroyed. Sometimes the threaded part of the handle is cut off. If the user begins to notice that oil leakage is observed on the shift shaft, this is not always an indicator of a breakdown. Sometimes the permissible oil level in the gearbox is simply exceeded. The excess just needs to be drained.

It is worth remembering that improper start-up and adjustment can also lead to malfunctions during the operation of the gearbox, therefore the manufacturer advises to carefully study the instructions before using the equipment.

The following is devoted to the disassembly and repair of the gearbox.

Consider the most common MB-1 faults:

In case of oil leakage along the output shaft, the first thing to do is to remove the axle shaft cover and replace the oil seals.
What to do if the gearbox jams? In this situation, you need to disassemble the walk-behind tractor, where you need to replace the broken chain.
If there is no kinematic connection inside the gearbox, then the dangling sprocket in the block needs to be replaced.
Faulty gears: do not engage at all or do not shift. There may be several reasons for such a breakdown. The first shattered switch cracker. The second cut off the threaded part of the shift knob. In these cases, we simply replace the defective parts with new ones.
Oil leakage along the shift shaft. The first thing we do is check the oil level in the gearbox. If its excess is found, then drain the excess, and if, on the contrary, add.
Worn lip of the shaft seal. Everything is simple here: we disassemble the gearbox and replace the worn cuff with a new one.
The overrunning clutch restoration should be carried out as follows: remove the starter, remove the clutch, and grind the grooves for the balls. A little oil needs to be poured inside to minimize the friction of the coupling and shaft. We set everything back.

Motoblock MB-2

This unit is an improved model of the MB-1 walk-behind tractor. It features a reinforced gearbox, differential lock, imported engine and other features. All this allows him to be maneuverable and convenient in work, have good tractive power, and be multifunctional, using attachments.

It is thanks to these qualities that MB-2 is very popular among buyers.

Do-it-yourself Neva MB-1 and MB-2 walk-behind tractor repair according to all instructions

The first Neva walk-behind tractors appeared in the 80s. Today, they not only have not lost their popularity, but have become even more in great demand.

Thanks to the constant modernization of models, Neva units delight their customers with an affordable price, good durability, high quality of all components and a long service life. Among the many models of this brand, we will talk about the two most popular: the MB-1 and MB-2 walk-behind tractors. We will learn not only their features, but also try to disassemble the most common causes of their breakdown.

Motoblock MB-1: frequent breakdowns of the unit and their solutions

This walk-behind tractor can be safely called the first-born in the production of Niva. Of course, by now it has been largely modernized and acquired a more modern design. With the help of such a unit, you can effectively process the site absolutely in any weather. It will excellently recommend itself both on pliable sandy soil and on solid ground. And the cast iron cylinder liner ensures its reliability and long service life.

Now we will analyze the most frequent cases of breakdowns of this unit. Usually, all repair instructions can be found in the instruction manual, so if you still have it, you can safely use its instructions. But if this thing is lost, then you can use our advice.

Malfunctions Neva MB-2:

Semi-axle separation is not possible. In this case, check the drive adjustment. If it is incorrect, change the cable tension.
Self-switching off of gears or lack of fixation. This problem can occur in three cases, or the shift control system is broken. Then you need to loosen the screws that hold the board, engage 1st gear and tighten the screws back. Either the spring is broken or the board retainers are worn out. In this case, you just need to replace the broken parts. Either the cheek of the fork is worn out, then you need to disassemble the gearbox and replace the broken part.
If there is no kinematic connection inside the gearbox, then the shift fork itself must be replaced. There may also be an option that the welding of the gear with the block shaft was interrupted.

It is worth remembering that before you independently repair the Neva walk-behind tractor, you should carefully read the repair instructions that the manufacturer offers you. If you do not have such instructions, then you should use the tips above. Of course, if you do not have special skills to repair such equipment, then it is better to entrust the Neva MB walk-behind tractor to specialists. There are many service centers in which they will carry out a complete diagnosis of equipment and be able to identify the exact cause of the malfunction.

Remember, in order for the walk-behind tractor to serve you for many years and not to succumb to any malfunctions, you need to make a timely oil change and adhere to all operating conditions.

DIY repair of the Neva MB 2 walk-behind tractor

Auto mechanic specializing in agricultural machinery

Over, the price of agricultural machinery is quite affordable. Reliable and multifunctional motoblock assistants have appeared, which quickly and efficiently process a plot of land: plowing, hilling, planting, mowing, as well as removing garbage and snow in the local area. All these and other operations are performed by means of attachments driven by the gearbox of the MB 2 walk-behind tractor.

The gearbox can be repaired by hand

If the device fails, the process of correcting breakdowns is identical to other designs of walk-behind tractors. The most common violations in the operation of mini tractors, which are worth paying attention to:

When the rotation of the crankshaft stops, it is necessary to unscrew the gearbox and carefully inspect the internal elements for destruction;
If white smoke poured out of the muffler, the reason is in the carburetor;
The engine slows down and stalls, you need to wait for the engine to cool, then check the oil level and clean the cylinder head and block surface from dirt.

Basic rules for using the mechanism will help you avoid costly repairs to the unit.

Gearbox repair and malfunction

If there are moving parts in the cultivator device, it means that machine oil must be used. For high-quality operation of the mechanism, only a high-quality product is used and the oil level is monitored. If it is necessary to carry out repair work, all stages can be conditionally divided into:

Drain the oil and clean the surface of the gearbox from contamination.
The case is disassembled and each element of the device is inspected.
The necessary details are changing.
Reassembly with new lubricant filling.

Dismantling the gearbox of the Neva MB 2 walk-behind tractor is presented in detail on our website.

The main reasons that can lead to failure of the gearbox:

Oil leaks through a worn cuff;
Poor quality lubricant;
Drips on the output shaft due to wear on the lip of the cuff;
Block sprocket break;
Open circuit;
Wear on the thread of the gear lever.

Gearbox device

The purpose of the device is the transmission of rotary motion from the engine to additional attachments. The design of the gearbox consists of a gear shift system, a clutch and a shift lever. When you press the lever, a low gear is activated. If the handle is moved all the way, an overdrive will be engaged.

In this you will learn about the pros and cons of this walk-behind tractor:

Device by assembly type

Depending on the ability to disassemble and repair the device, converters are divided into two types:

A budget option that installs inexpensive disposable parts. If the spare part fails, it is better to replace the gearbox with a new one.
A collapsible design that allows you to easily replace a failed spare part. It can serve reliably for several years without breakdowns.

By the type of gearbox design, the following are:

Corner.
Downward.
Gear.
Worm gear.

This type of mechanism is equipped with a reverse motion of the walk-behind tractor.

Oil change

The lubricant level indicates the need to change it. If the time has come, then the procedure is performed as follows:

To begin with, choose a horizontal platform and put the Neva MB 2 walk-behind tractor on it.
They find a plug for filling the engine oil on the engine and clean it and the surface next to all kinds of contaminants. The plug, which is also a probe, should be at the bottom of the side.
New oil is poured through the hole and the liquid level is checked with a dipstick.

Oil seal replacement

If there are oil leaks, this means that it is time to change the oil seal. The work should be done as soon as possible, otherwise you can be left without a walk-behind tractor, because the movement of metal elements inside the device will lead to its destruction.

The sequence of operations is as follows: