Setting valve clearances in walk-behind tractors

How to adjust the valves of a walk-behind tractor

The walk-behind tractor has long been known as a means of plowing land. For normal operation of the device, adjustment of the walk-behind tractor
, which should be created at least once a year. > myth unit significantly simplifies human work. With various attachments, it can do all agricultural work. It is also used for vehicles for cargo transportation. But he will deliver himself to significant distances on his own.

Motoblock and its device

Technical service is an essential element of caring for a walk-behind tractor. This also includes the adjustment of certain fundamental components responsible for the properties of the unit. Valves and carburetor are related to them. Their serviceability one hundred percent affects the operation of the engine. If they malfunction, the gearbox and the entire chassis of the vehicle, along with control services, will not work correctly. To maintain the unit in normal condition, you need to have a good understanding of its structure. What is needed as part of the walk-behind tractor

includes:

engine;
box;
chassis;
control system;
supply system.

Adjusting the valves of a walk-behind tractor with a gasoline engine.

Each separate walk-behind tractor has its own equipment. The engine used for them is two-stroke or four-stroke. In terms of power supply, they can be diesel or petrol. Currently, in most cases, units are produced with four-stroke engines. They possess the highest technical features. Large vehicles are usually equipped with diesel engines. Other walk-behind tractors are equipped with gasoline-powered engines.

The torque from the motor is transmitted to the wheels of the car using a gearbox. It includes:

gearbox;
gearbox;
clutch;
differential (not in every model).

The chassis of the unit consists of wheels. They are pneumatic and metal. The wheels are installed on the frame along with the rest of the block.

On and around the handles there are details that allow for accounting (software) management. This is the clutch lever, various levers and buttons for configuring the direction of movement and for switching speeds. At the same stage there is a button to stop the motor.

Adjusting the valves of the Chinese engine Lifan 168F-2,170F,177F Lifan walk-behind tractor

KEY-DOP

Adjusting the engine valves

LIFAN or similar Chinese engines
for walk-behind tractors
, cultivators, motor pumps, generators.

The power system consists of a fuel tank, carburetor, and fuel supply pipes. The main part is the carburetor. It does the function of a mixer. This popular rumor mixer mixes gasoline with air and delivers this mixture to the engine cylinders. Typically, a carburetor consists of smaller parts:

float chamber;
diffuser;
dampers;
spray;
mixing chamber;
other details.

Different models of walk-behind tractors have their own carburetors, which are regulated by different methods.

Adjustment of valves

To adjust the valves on walk-behind tractors, you need to prepare the following tools:

spanners;
screwdrivers;
probe, also called a razor blade.

There are variations of certain types of engines that require other additional tools. Adjusting the valves means setting rational valve clearances for walk-behind tractor engines. The size of the gap is indicated in the annotation for the unit. The design of the engines on each model of the unit is different. However, the complete sequence of actions is as follows:

the motor casing is removed;
the valve cover is removed;
adjustment is made;
the valve box cover is installed;
the casing is installed.

KEY-DOP

The valves are easy to find under the valve cover. Inspect the gap size with a feeler gauge. In most cases, the intake valve clearance is 0.15 mm, exhaust valve clearance is 0.3.2 mm. With the correct clearance, the feeler gauge fits freely under the valve. If this is so, then our client remains fine. To adjust, you need to loosen the nuts and insert the dipstick again. Adjust the gap and tighten the nut. Check clearances again. If results are normal, install the valve box cover and housing.

Before making adjustments, it is recommended to let the engine run and then cool it. The valves on an Agro walk-behind tractor adjusted a little differently

warm up and then cool the engine a little;
remove the oil bath from the air filter;
remove the flywheel housing;
align the “0” mark on the flywheel with the mark on the cylinder;
the valve box cover is removed;
clearances are checked;
gaps are adjustable;
tightened, our client is left with the nuts;
the cover and casing are installed in place.

Approximately the same scheme is used to make adjustments on Patriot and Agros walk-behind tractors. For the Cascade unit, you need to do the following:

remove the casing;
remove the valve cover;
turn the flywheel until the intake valve is pressed;
measure and adjust valves;
place the cover with the casing to the area.

Adjusting the valves of a Honda petrol engine walk-behind tractor.

Of course, use the same method when adjusting the valves on the Ural and Centaur units.

Remove the timing chain cover

A separate article on removing the timing cover on Emgrand and X60 engines (analogous to Toyota's 1ZZ-FE).

Remove the timing chain and rotate the crankshaft

so that the piston in the first cylinder is at top dead center.

Check the clearances in the valve drive shown in the figure

Write down the valve number

and the size of the gap, if it does not meet the permissible limits.

After this, you can move on to the remaining valves. To adjust them, you need to rotate the crankshaft 360° (one revolution). Thus, the top dead center of the compression stroke will be in the 4th cylinder.

Measure the gaps in the valves indicated by arrows

and write down the gap sizes.

Adjusting the walk-behind tractor carburetor

Instability of the engine speed of the walk-behind tractor indicates that the carburetor needs adjustment. The need to perform this procedure, as a rule, arises before the start of the agricultural season, when the equipment has not been used for a long time, or after it, when the walk-behind tractor has been subjected to significant loads for a long period of time. Before proceeding with adjustments, it is necessary to warm up the engine. The actual work process looks like this:

The screws regulating low and maximum throttle are screwed in completely, after which they are loosened by about one and a half turns.
The engine starts and warms up for about 10 minutes.
The lever that controls the operation of the power plant must be set to the minimum position, but the motor should not stop.
The throttle valve adjusting screw will help you adjust the minimum idle speed so that the engine operates stable, without any extraneous noise or stopping.
Rotating the screws makes it possible to accurately determine the amount of combustible mixture that enters the engine.
Tightening the screw helps enrich the mixture, while unscrewing it, on the contrary, increases the volume of air entering the engine;

Using the idle screw, you should adjust the maximum idle speed. The same should be done with minimum speed, using the throttle stop screw. The essence of this adjustment is that the damper screw allows you to adjust the angle at which it is closed;

The lever responsible for controlling the engine should be moved to the “gas” position. If the operation of the walk-behind tractor still cannot be called stable, the full throttle screw is adjusted until the ideal speed is observed. However, the maximum permissible number of propeller revolutions is 2.5.

The accuracy of carburetor adjustment can also be determined by how the spark plug looks after a short period of operation under load. If the working mixture is ideal, then there will be no soot or traces of fuel on the spark plug, which indicate that the fuel mixture is too lean or, conversely, too rich. It should be noted, however, that carbon deposits or traces of fuel on a spark plug can indicate not only incorrect adjustment, but also more serious problems with the walk-behind tractor, including a faulty ignition or cooling system.

Adjusting the valve clearance of the walk-behind tractor

Over time, under significant loads, the valve clearance of the walk-behind tractor engine changes. The reason for this may be wear and tear of parts. Insufficient distance leads to the fact that the valve timing stages change significantly, as a result of which it is not possible to achieve a sufficient compression ratio, the power plant operates intermittently and does not reach the declared power. In particularly serious situations, even deformation of the valves can be observed. If the gap is too large, then significant mechanical noise is recorded, the gas distribution phases also change significantly, the valves open for too short a time, due to which the cylinder does not fill properly, power drops, and malfunctions occur. Adjustment of the gaps is necessary as soon as the engine operation becomes incorrect or occurs with significant noise. Ideally, the engine being adjusted should be cool.

So, first you need to get to the flywheel. It is on this part that the value of the top dead center is marked. The flywheel is hidden under the casing, and therefore you will have to remove it. Before removing the casing, the oil bath of the air filter is removed. You can make the task easier when removing the casing if you secure all the latches with rubber bands. Use a wrench to unscrew all the bolted connections, after which the cover can be removed without any problems.

On the flywheel you can see marks that indicate TDC, as well as the values of 5, 10 and 20 degrees. The 20 degree mark indicates the injection of the combustible mixture. The flywheel should be brought under the top dead center, focusing on the corresponding division. The valve cover is unscrewed and removed.

During the adjustment process you need to use the following tools:

Screwdriver;
Socket wrench 10;
The blade is 0.1 millimeter thick.

According to the technical data sheet, the valve clearance of the walk-behind tractor engine is from 0.1 to 0.15 millimeters, and therefore, using a blade, you can adjust it very accurately. However, you need to pay attention to the fact that some blades have a thickness of 0.8 millimeters, which is unacceptable. The exact value can be found with a micrometer or from the information on the manufacturer’s website. The adjustment is carried out as follows:

Screwdriver;
Loosen the nut, insert the blade and begin to tighten;
You should focus on the blade while carefully tightening the nut;
The adjustment is carried out until the free play of the valve is eliminated. It should fit quite tightly.
Reassemble the casing in reverse order and replace the oil bath.

If all manipulations are carried out without errors, the engine will run smoothly and without unnecessary noise.

Conclusion

A walk-behind tractor can perform a very wide range of work , but this requires some effort on the part of the owner of this device. This is not only about replacing faulty parts and components, but also about timely adjustment of some device components.

In particular, the correct operation of the walk-behind tractor engine will depend on how correctly and timely the valves are adjusted.

And it doesn’t matter whether it’s a Honda walk-behind tractor, be it a Vityaz 8hp walk-behind tractor and its correct regulation, we are talking about adjusting the valves on a diesel walk-behind tractor, or you need to adjust the valves on a gasoline Forte walk-behind tractor

It is recommended to do this after each season, but there are cases where such adjustment is required at least twice during a certain period of work. The main signs of this are atypical noises in the carburetor area, knocking - as a rule, uncharacteristic sounds during operation of the walk-behind tractor.

If this is detected, and if the valves do not support control by the remote control in the walk-behind tractor, you need to immediately inspect and decide on action, especially since this procedure is quite simple and can be done at home.

A walk-behind tractor trolley is a useful device that you can assemble with your own hands.

Source

Agriculture has been in decline for many years due to the period of perestroika in our country. This has led to a certain lag in terms of technology, as well as a loss of special interest in this industry.

However, thanks to some positive initiatives by the government, the agricultural sector has gradually started catching up and farmers have started emerging who are professionally involved in this industry. Improvements also included specialized equipment, which became widespread in rural areas.

READ How much oil to pour into the Centaur walk-behind tractor engine

Among this equipment, we can distinguish the category of walk-behind tractors, which are actually mini-tractors, but with slightly less power. They more than make up for this deficiency with the agility and mobility they exhibit.

However, there are some decent Chinese models that are almost as good as ours.

In particular, we are talking about the Zubr diesel walk-behind tractor , known to many farmers for its reliability.

About the design of walk-behind tractors and valves

Motoblocks Cayman, Patriot, Texas, Foreman, Crosser, Viking, Forza, Sadko, Don are a rather complex technical device , consisting of several main working units: engine, transmission, chassis and controls.

Understanding the design of a walk-behind tractor is very important, because the correctness of repair and adjustment work depends on it.

Let's look at each node in more detail:

Engine . Depending on the configuration, 2-stroke and 4-stroke engines can be used. At the moment, 4-stroke engines are most widespread because they have higher performance indicators.
In addition, engines are divided into diesel and gasoline. The former are most suitable for large-sized units, and the latter – for small and medium-sized walk-behind tractors.

For more information about the operation of the walk-behind tractor engine, see the video below:

Transmission . The torque that is transmitted from the engine to the wheels is carried out through the transmission. It includes a gearbox, gearbox, clutch system and differential (for some models).
Depending on the type of gearbox and clutch, not only the cost of the walk-behind tractor is determined, but also the operating principle of these components.
Chassis. Most walk-behind tractors have a pair of wheels of various types - pneumatic or metal, equipped with lugs. In addition, the chassis includes the frame itself, on which all other elements of the walk-behind tractor are located - engine, gearbox, etc.
Control system. All control of the walk-behind tractor is located at arm's length from the operator, i.e. on the handle and in its immediate vicinity. This includes the clutch lever, buttons for shifting speeds and changing movement, emergency engine stop, etc.

Carburetor walk-behind tractor

As for the carburetor, it is part of the engine power system. Acts as a kind of mixer that mixes liquid fuel with air to obtain a fuel mixture, which then enters the engine cylinders. Structurally, it looks like this:

float chamber;
diffuser;
spray;
throttle and air dampers;
mixing chamber;
jet, etc.

This is a description of a standard carburetor , but different models of walk-behind tractor, such as Huter, Profi, Plowman, Champion, Carver, Husqvarna, may use different carburetors, respectively, and the adjustment will be different.

Engine to valve ratio

The walk-behind tractor is a complex agricultural unit, which includes the following units:

Engine;
Method of transmission;
The system works;
Steering;
Supply system.

The engine is the power mechanism of the walk-behind tractor. The following types of engines exist:

By configuration method:
2 stroke
4-stroke.
By type of fuel used:
Diesel fuel;
Petrol.

Recently, manufacturers have been producing 4-stroke engines with high technical characteristics.

Diesels are installed on large units, on small and medium-sized gasoline engines, widespread among farmers, with a power of 4-9 hp.

Internal combustion engine. The main device in which the process of converting the thermal energy of fuel combustion into mechanical energy occurs.

The energy conversion process is carried out in 4 stages:

Starting fuel;
Compression of the combustible mixture;
combustion;
Release.

Fuel material enters the combustion chamber through the intake manifold. The valve elements close, the piston moves upward, compressing the working mixture. When the spark plugs are turned on, the discharge ignites the flammable material. As the temperature rises, the mixture expands, pushing the piston down. Thermal energy is converted into mechanical energy. When the valves open, gases are released into the exhaust system.

READ How to Connect a Rotary Mower to a Walk-Behind Mower

The reason is wear and tear of the elements. A small gap changes the valve timing. The engine does not operate at the stated power. With a large gap, mechanical vibrations occur, which lead to deformations. Due to the short opening of the valves, the cylinder is not completely filled. This leads to glitches, glitches and reduced productivity.

Adjusting walk-behind valves is a necessary maintenance procedure.

According to technical regulations, it should be carried out once a year. In case of machine malfunction, the valves can be adjusted 2 times a year.

Using the example of a Chinese automobile engine from LIFAN, we will consider a number of problems; in this case, it is also advisable to adjust the valves on a 6.5 hp walk-behind tractor. Lifan:

If there is a “kickback” on the starter handle when starting the engine;
If you feel a distinct knock in the cylinder head while the engine is running;
If the engine is started intermittently, it will settle down and start very "hot", starting correctly only after cooling;
When you hear the muffler pop out and the tractor behind you loses power.

Required Tools

To adjust the carburetor valves, you will need a minimum list of handy tools:

razor blade or feeler gauge;
minus screwdriver;
spanner wrench

Using these simple tools you can adjust most carburetors.

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Gardening and caring for plants and trees have always been considered one of the most difficult types of work, as they require significant time and effort. The Marolex sprayer is the ideal solution for your garden.

Labor-intensive gardening work can now be done using a walk-behind tractor. Here you will learn how to plant potatoes with a walk-behind tractor.

It is important to understand that valve adjustment means setting the optimal clearance, which is directly stated in the operating instructions for each specific model.

Step-by-step instructions for different models

Lifan 6.5

Adjusting the valves on the Lifan 6.5 walk-behind tractor consists of setting the correct gap under the valves. The sequence of actions will be as follows:

Remove the casing to get to the flywheel.
Remove the valve cover. Below it there are two valves - inlet and outlet.
To check the intake valve clearance, you will need a 0.15 mm feeler gauge, and for the exhaust valve, a 0.2 mm feeler gauge. When adjusted correctly, the dipstick should pass under the valve quite freely.
To adjust, loosen the fastening nuts using a wrench. We insert the dipstick between the valve and the piston so that it does not slip, but is held tightly enough in this position. We tighten the nut.
Replace the valve cover and flywheel housing.

Adjustment of devices Neva mb 2, Zirka 105

The process of adjusting the valves on the Neva MB 2 walk-behind tractor and a similar Zirka 105 walk-behind tractor:

Let the engine run and then cool a little.
We remove the casing.
We remove the valve cover and get to the flywheels that are under it.
Unscrew the locknut.
The blade that we insert into the gap should pass very freely between the piston and the valve .
Screw the entire system back.

How to properly adjust the valve of a Zip walk-behind tractor

What is the procedure for adjusting the valves on the popular zip walk-behind tractor:

Open the flywheel.
Unscrew the valve cover clockwise.
We check the gap with a feeler gauge exactly as described above.
Use a wrench to turn the nuts and loosen them a little.
We close the system and conduct testing.

How to set up on an Agro walk-behind tractor

The valves on the Agro walk-behind tractor are adjusted as follows:

We warm up the engine , and then give it some time to cool down.
Remove the oil bath of the air filter.
Next, you need to unscrew the flywheel housing, which is secured with 6 bolts.
The marks on the flywheel are 0 (top dead center), 5, 10 and 20 (fuel injection). We compare the dead center of the flywheel with a mark located on the cylinder so that they are opposite each other.
Next, remove the valve cover.
Below it are two valves. Loosen the locknut, then insert a razor blade under the valve. The blade must pass freely between the piston and the valve.
Having achieved this, tighten the nut back . Then we return the valve cover and flywheel housing to their place.

It is worth noting that identical adjustment steps are carried out to adjust the valves on the Patriot walk-behind tractor. The Agros walk-behind tractor and its valve adjustment also correspond to the MB 1 walk-behind tractor.

So, if necessary, you can use an identical scheme.

Cascade

Adjusting valves on the Cascade walk-behind tractor:

Remove the casing from the flywheel.
Remove the valve cover.
Turn the flywheel until the intake valve is pressed. Accordingly, the exhaust valve will be depressed.
Next you need to achieve the correct clearance for each of the valves. According to the instructions, for the inlet this parameter is 0.15 mm, and for the exhaust - 0.20 mm.
Using a feeler gauge, check the existing gap between the valve and the piston. If the dipstick slips a lot, or it does not pass between them at all, then we will need adjustment. If there is no probe, then you can use a razor blade, the thickness of which is 0.1 mm.
To adjust, loosen the fastening nut, and then insert the feeler gauge into the space under the valve. Its optimal position would be a fairly tight movement between the piston and the valve, without slipping.
If everything works out, tighten the nuts back , and then put the valve cover and casing back in place.

You should also approach valve adjustment on a Ural walk-behind tractor based on the instructions described above.

The operating scheme is arranged in an identical way, so you can use one algorithm of actions, exactly the same as for adjusting the valves on the popular Centaur walk-behind tractor.

Adjusting the valves on the Gili Emgrand engine (aka the engine from Lifan X60)

First, remove the plastic engine cover,

I hope there won't be any problems with this. You also need to remove the ignition coils, otherwise it will be difficult to remove the cylinder head cover.

Disconnect the high-voltage wires from the coils and unscrew the mounting bolts.

Remove the coils from the spark plugs.

Remove the cylinder head cover.

To do this, first disconnect the terminals from the battery, as all textbooks teach.

Remove the two ventilation hoses from the cylinder head cover.

Unscrew the bolts and nuts securing the cover and remove it.