How to check the solenoid valve and starting enrichment on a 4t scooter?

What is a starting enrichment

A starting enricher (electrovalve) is a device designed to supply an additional amount of air-fuel mixture into the combustion chamber during a cold start of the scooter engine. The fact is that when starting the scooter when cold, the engine requires an enriched mixture. The supply of such a mixture is ensured by the carburetor solenoid valve . If the starting enrichment is in good working order and there are no breakdowns in other engine elements, the scooter engine starts easily even at temperatures around zero degrees.

Signs that a check is needed

If difficulties arise with starting the engine and in a number of other situations, it is necessary to be able to check the functionality of the starting enrichment. Thoughts about a malfunction of the solenoid valve may arise in different cases.

Let's take a closer look at the main reasons:

• the first morning start of a cold scooter engine is problematic;
• it is difficult to start a cooled scooter engine after a long stay;
• fuel consumption significantly exceeds the consumption indicated in the passport;
• The scooter's power unit is quite unstable at idle;
• a warm engine does not maintain speed, and a cold engine functions intermittently.

Any of these problems should make the scooter owner think about a possible malfunction of the solenoid valve.

A faulty enrichment device can be in two positions:

• with the solenoid valve needle constantly extended;
• in the initial state, when the needle does not protrude.

It is necessary to be able to check the functionality of the starting enrichment if difficulties arise with starting the engine.
Each case has a different effect on the operation of the motor. The first situation makes it difficult to start the engine of a cold scooter. An attempt to start the engine by pressing the kickstarter, as well as starting with an electric starter, are unsuccessful. In the second case, the engine starts without problems, but during operation it consumes an increased amount of gasoline. Increased fuel consumption is associated with engine operation on a highly enriched mixture.

Scooter starting enrichment device

There are two types of starting concentrators - manual and automatic.

The manual (mechanical) starting enrichment requires adjustment - it must be opened at startup and closed after the engine warms up using a cable on the steering wheel. But manually opening and closing the additional channel for supplying the mixture is inconvenient. An automatic starting enricher (thermoelectric valve) is installed on most modern 2t and 4t scooters. We will learn about the device of the automatic starting enrichment further.

1. 
   Solenoid valve body

2. Ceramic heater
3. Drive (powder)
4. Stock
5. Pusher
6. Damper
7. Fuel chamber
8. Float chamber
9. Starting fuel jet
10. Spring

The scooter carburetor has a small additional fuel chamber 7, which is connected to the main float chamber 8 through the start nozzle 9. The tube from chamber 7 leads to the mixing chamber into which air is supplied and from which the air-gasoline mixture goes into the engine. A valve 6 can move in the mixing chamber, similar to a carburetor throttle valve, only much smaller in size. Just like the throttle valve, the starting valve contains a spring-loaded needle that closes the fuel channel when the valve is lowered. Valve body 1 is wrapped in thermal insulation (polyethylene foam) and covered with a rubber boot. This enricher design is used on almost all modern scooters.

Older models may use a design without an electric heater, heat is transferred to the drive through a copper heat-conducting cylinder directly from the scooter's engine cylinder, and a membrane . One cavity of the flask, where it is located, is connected through a thermal valve to the intake manifold, which is mounted on the cylinder head.

The principle of operation of the scooter carburetor solenoid valve

When the engine is cold, the valve with the spool needle 6 is raised as high as possible (open). The needle opens the fuel supply channel, and the flap opens the air supply hole. At the first engine revolutions, a vacuum is created in the emulsion channel and gasoline located in chamber 7 is sucked into the engine through channel A, causing a strong enrichment of the mixture and facilitating the first flashes in the engine. After the engine has started, but has not yet warmed up, it still needs a rich mixture. The enricher works like a parallel carburetor - gasoline enters it through jet 9, mixes with air and enters the engine.

When the engine is running, alternating current from its generator is always supplied to the contacts of the ceramic heater 2 of the thermoelectric valve of the starting system. Heater 2 warms up drive 3. As the engine and drive warm up, the rod gradually extends by 3 ... 4 mm and drives the damper through pusher 5. Thus, the engine warms up along with the thermoelectric valve, the spool with the needle drops and closes the air and fuel channels, and the mixture gradually becomes leaner. After 3...5 minutes, the damper closes completely and the degree of enrichment of the mixture on a hot engine is regulated only by the carburetor idle system .

When the engine stops heating of the valve stops , the damper drive cools down (the powder is compressed) and under the action of spring 10, pusher 5, rod 4 and damper 6 return to their original position, opening the channels for subsequent start-up. Cooling down and returning to its original position also occurs within a few minutes.

The disadvantage of this type of enrichment is that it operates separately from the engine. For example, very often, especially in warm weather, while the engine is still hot and there is no need to enrich the mixture, the thermoelement is already cooling down. We start the engine and it gets a rich mixture.

Where is a solenoid valve used?

The electromagnetic shut-off valve is intended for use as a control and shut-off device for rapid remote control (switching off or switching on) of liquid, steam, air or gas flows of any pipeline system.

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The design of a scooter carburetor and its operating principle

The design of a scooter carburetor is quite simple; Once you understand it, you will be able to understand how to properly configure the carburetor so that the vehicle does not let you down in bad weather, how you can tune it and improve the performance of the engine. You will be able to control the quality of the mixture and many other processes that affect the operation and operation of the device.

More detailed diagnostics

To avoid problems with the moped and be completely confident in the serviceability of the scooter, you need to conduct a more complete check. One of the main characteristics of a working scooter motor is normal compression. More on this indicator of the condition of the piston group later.

Scooter compression check

• Unscrew the spark plug (at the same time assess its condition)
• Screw the compression gauge tightly into the spark plug hole
• We press the kickstarter lever several times, thereby creating pressure in the piston

Attention! During diagnostics, you should not try to start the scooter engine using an electric starter.

The principle of operation of a scooter carburetor

The carburetor design of a 4t scooter is not very complicated. The basic principle of its operation is as follows: a certain amount of fuel and oxygen enters the float chamber of the device, where they are mixed in the required proportions and supplied to the combustion chamber of the engine.

The design of a 4-stroke scooter carburetor may vary slightly depending on the model, but in general it is the same for all types of carburetors. The float version of products is most often used. It is distinguished by the presence of a float chamber in which fuel is mixed with air, after which the finished mixture is fed into the cylinder. In order for air to enter the fuel in the required proportion, the carburetor includes the following elements:

• Jets.
• A needle that meters the supply of oxygen.
• Spool.
• Throttle valve.

Sometimes the design of a 4t carburetor on a 50cc scooter includes an element such as an accelerator pump. It works in tandem with a starting mixture enricher. These devices help the scooter engine to work correctly and start in damp and wet weather. The correct operation of the motor depends on the coherence of the devices, so it is important to pay attention to their settings.

Scooter starter booster

Most often, scooters are equipped with an electric starting enrichment; on older models you can find a manual one. The task of this device is to create the right mixture in order to start the engine after a long period of inactivity.

The carburetor has an additional channel for connecting the enricher. If the device is automatic, the channel opens itself when you try to start the scooter and closes as the engine warms up. If the enrichment is manual, you need to close its valve yourself. The operating principle of the device is as follows:

• Inside the housing there is an element heated by electricity, which pushes out a needle that blocks the fuel channel.
• After the engine is stopped, the needle will be retracted.

Float chamber device

Mixing of fuel with air in the carburetor occurs with the participation of the float chamber; Thus, the finished fuel, saturated with the required amount of oxygen, enters the combustion chamber, where it explodes and sets the scooter in motion.

From the gas tank, fuel enters the carburetor through special pipes. But mixing cannot occur in them, so first the fuel ends up in the float chamber, and only then it is enriched with oxygen and further moved. To ensure that gasoline does not flow continuously, but in the right quantity, the carburetor is equipped with a special system with a float and valve. When the chamber is full, the float rises and the valve blocks fuel from entering the carburetor; when the float is lowered, the flow of fuel resumes.

Fuel dosing system design

The mixture is supplied to the cylinder in finished form, so it is necessary to control its quality. For this purpose, the carburetor has a special needle with grooves and a locking ring. The position of the needle depends on the position of the ring: the higher it is, the richer the mixture, and vice versa. Modern carburetor models allow you to tune them without disassembling them.

For proper operation of the device, the diameter of the main jet is important. It is selected based on motor power and diffuser size. When tuning, the nozzle hole can be enlarged.

Troubleshooting

The first and main sign that the equipment needs repair is the inability to start the engine. Scooter repair begins with identifying the fault and then eliminating it. In this case, the breakdown must be looked for starting from the place where the thermal energy of the burnt fuel is converted into mechanical energy of the rotating crankshaft of the engine. So let's get started:

— determine whether fuel enters the combustion chamber,

— is there a spark between the spark plug contacts?

If all of the above factors are present, then the following malfunctions are possible:

1. There was a breakdown of the spark plug insulator. To do this, simply replace the spark plug.

2. The ignition timing is off, and the fuel mixture does not ignite at the moment when the piston almost reaches its top dead center (TDC). Here you can no longer do without an indicator, with the help of which the position of the piston in the cylinder relative to TDC is determined, and at what moment a spark appears on the spark plug, igniting the fuel mixture. In this case, repairing the scooter will consist of setting the correct ignition timing recommended for this type of engine.

If there is no spark at the spark plug, then the following problems may occur:

1. The spark plug is faulty.

2. The candle holder is faulty.

3. The armored wire is broken.

4. The ignition coil has burned out.

5. If the ignition is electronic, then either the ignition unit or only the Hall sensor may be damaged.

If the fuel mixture does not enter the combustion chamber, this may be caused by such problems.

If the scooter is two-stroke:

1. fuel filter clogged;

2. The carburetor is clogged or broken.

If it is a four-stroke engine, then a malfunction of the gas distribution system (burnouts or bent valves) may be added to the breakdowns.

Why adjust the carburetor?

Carburetor adjustment may be required in the following cases:

• The spark plugs are serviceable, but do not work very well; their color has changed to black or yellowish.
• The engine does not provide the required power
• Scooter won't start
• Fuel consumption has increased excessively.

All these problems in most cases are caused by an insufficiently enriched or, conversely, overly enriched mixture with oxygen, and they can be corrected by correctly adjusting the carburetor.

The settings, regardless of whether you have a 2t or 4t scooter, have three phases and are made as follows:

• Idle speed adjustment
• Setting the fuel level
• Adjusting the quality of the mixture.

On some carburetor models there is no screw that adjusts the fuel quality, so you have to disassemble the carburetor to change the position of the needle.

The idle speed adjustment is carried out after the engine has warmed up: this takes no more than 15 minutes. For this purpose, the design provides an idle screw. It allows you to make the engine stable by selecting the desired idle speed. When the screw is tightened, the speed will increase, and when it is rotated counterclockwise, it will decrease.

It is important to adjust the quality of the mixture. If it is too lean, the scooter will ride with difficulty, and the engine will noticeably lack power. If the mixture is too rich, the spark plugs will turn black and quickly fail. Fuel quality adjustment is usually carried out using a screw located on the carburetor body. To enrich it you need to turn it clockwise, to lean it counterclockwise. If there is no screw, the carburetor is opened, the locking ring on the needle moves up for a richer mixture, down for a leaner one.

Adjustments are made as follows:

• Start the engine and warm it up for 10 minutes, after which you need to turn it off
• The screw must be tightened clockwise until it stops, but without force.
• After this, it is unscrewed counterclockwise 1.5 turns
• The engine needs to be started and the screw turned an additional 1/3 turn in the same direction. Wait 2 minutes
• As the speed increases, you need to unscrew the screw an additional 1/4 turn and observe the reaction for about 2 minutes. If the speed does not drop, repeat the steps
• If the speed begins to decrease, the screw must be turned clockwise 1/4 turn.

Ideally, the engine will operate exactly at 1.5-2 propeller revolutions, but its position depends on the quality of the fuel. In the case of a needle, the quality of the mixture will vary depending on the position of the needle locking ring. The disadvantage of such a carburetor is the small number of needle positions and the need to disassemble it each time to make adjustments.

You can adjust the fuel level in the chamber as follows:

• Unscrew the drain screw
• The phone is lifted up
• You need to check the fuel level while the engine is running. The melting level is slightly below the skirt located on the float chamber cover
• Most often, the level rises above normal and the carburetor overflows, so you need to adjust the float so that it fires earlier. To do this, the needle holder is usually bent. A lot of force is not required, only a few mm are needed.

How to check PP with a multimeter on a moped?

The relay regulator on a Chinese scooter is checked using a multimeter with a voltmeter function. For this purpose, a simple DT-830 (or equivalent) is usually used. It is better to carry out diagnostics and measurement of output voltage with the device removed.

Verification algorithm:

1. You need to unscrew the fairing with the central phase and find on the frame a device with 4 wires: red, green, yellow and white.
2. Then start the scooter and check the voltage at idle: measure it between the green and red wires, setting the multimeter to the maximum value of 20 V.
3. If the multimeter display shows a figure of 14.6-14.8 V, this is normal. For stabilizers on Chinese mopeds, this is the operating standard voltage. If at idle the multimeter shows a value of 15-16 V, this is a high voltage indicator. This indicates a malfunction of the relay regulator.
4. Then you need to check the voltage supplied to the lighting lamps. An alternating voltage is supplied to the central low beam (high beam) lamp, so the multimeter should be switched to the alternating current measurement mode with a parameter of 20 V.
5. Next, we measure the voltage between the green and yellow wires (green is the general electrical network of the moped). If the multimeter shows a network voltage of up to 12 V, then the electrical appliances are operating without additional load.
6. If at idle this value is 16 V or higher, and with a sharp increase in engine speed it jumps to 25 V, the device does not stabilize the voltage and, therefore, does not work. With such readings, the device must be replaced with a new one.

Using a multimeter, they check the relay regulator on a Chinese scooter.
In order to make a measurement, you need to:

• switch the device to the “KiloOhm” mode and remove the regulator;
• then place the probes on the first pair of terminals (AB). The tester should show a value of no more than 18 kOhm;
• after that, we change the position of the probes on the terminals in the opposite direction (VA) and measure the voltage again - the arrow on the device should show 0;
• then we install the probes on the next pair of terminals (SD) and measure the readings on this pair;
• swap the probes (DS) and measure the indicator again;
• the remaining measurements have no contact and are not checked. The indicator when checking them should be zero.

In this way, regulators are tested on popular Japanese models with small engine volumes from brands such as Honda (Leard, Dio, Tact), Suzuki, Yamaha.

Replacing a faulty relay regulator on a scooter is not difficult.

What is the carburetor of a Chinese scooter and its capabilities, disadvantages, tuning

The carburetor circuit of a Chinese scooter is, in principle, standard and suitable for both 2t and 4t engines. The design of the carburetor allows certain actions to be taken to improve its performance, however, if the engine is two-stroke, the efforts will not make sense.

The simplest approach is to replace the carburetor with a more advanced one, for example, with an accelerator motor, if you have a fairly old version without it. Most often, simple tuning is limited to replacing the main fuel jet, this is especially true for engines with low power. Replacing the nozzle helps to increase the fuel channel and, due to this, add a little power to the engine.

Quite often, more serious tuning involves the use of a 150 cc scooter carburetor. Interesting models with a diffuser diameter of 17.5 mm. It is great for 70cc piston. Less often you come across a large diameter of 19-24 mm, it is just ideal for a bored 150 cc piston engine. However, the diameter must be selected correctly, otherwise the motor will begin to choke.

Troubleshooting

Malfunctions of electrical equipment and fuel systems are the most regular of all problems that arise among scooter owners.

It often happens that a breakdown suddenly occurs to the scooter. Repairing the carburetor, as a rule, allows you to resume the functioning of your “faithful horse”.

Usually, to do this, it is enough to remove the carburetor, clean the dust from the outside and the tarry deposits of gasoline and other debris inside. Clean and blow out the air and fuel channels and jets, check the condition of the fuel needle and throttle valve, and then reassemble and adjust it.

Fixing more complex breakdowns at home is not always possible, since specific tools are often required that are not widely available.

Thus, for a technically literate person, repairing a scooter with your own hands will not be very difficult if you have minimal knowledge and skills in handling equipment, as well as the necessary tools.

Design and connection of a Yamaha scooter carburetor

The Yamaha Jog scooter is one of the most popular on the Russian market: this is explained by the simplicity and reliability of the model, and its affordable price. The carburetor design of this scooter is standard, so you can figure it out using the description given above. However, when installing it, inexperienced owners may encounter some difficulties, which we will help you sort out.

The device is worth considering in more detail. This will help you understand not only how to adjust the carburetor and use it correctly, but also how to connect it correctly.

• A starter enricher is attached to the carburetor body: it is small in size and housed in a plastic case. It has two bolts with rubber seals. The enricher is powered via a 12 V battery. This device is used to start the engine when cold, as it allows you to automatically enrich the mixture with oxygen.
• The fitting is connected to the fuel supply hose coming from the gas tank tap.
• If the enrichment unit needs to be removed, you will need to not only unscrew the bolts, but also disconnect the electric valve, to which there are only two wires.
• The mixing chamber has a special cover to which a bolt is attached. If you unscrew it, you can get to the throttle valve. This allows you to check whether the throttle cable is connected, and also to get to the needle that regulates the level of fuel and air supply. If the carburetor needs cleaning, you will definitely need to remove the throttle.
• The enrichment connector has two wire outputs, the yellow one is connected to the generator, the green one goes to ground. In principle, if you reverse the polarity, nothing will happen and the device will still work.
• For the enricher to operate, voltage must come from the battery. When the element inside the device heats up, the needle will extend.
• A special fitting is connected to the air filter, and there is a rubber elbow between them.
• There are several screws on the carburetor body with which you can adjust the idle speed and mixture quality.
• The float chamber is screwed from below and has 4 mounting bolts.
• There is an additional fitting for oil supply: it is the smallest.
• The second fitting is needed for communication with the atmosphere; you do not need to put anything on it.
• The third one is connected to a gas hose. It goes to the gas tank vacuum valve.

How to make a relay regulator with your own hands?

To make a relay regulator with your own hands, you need a diagram and a little knowledge. The model of a homemade regulator is based on the principle of disassembling the generator and outputting a separate end of the wire from ground.

To collect the stabilizer you need:

• disassemble the generator and remove the stator from the engine;
• then you need to unsolder the ground from the generator, solder a separate additional wire for the winding to it and bring it out. This wire will be one end of the winding. The second end is the generator wire;
• After removing the wires, you need to reassemble the generator in reverse order.

With this device, the generator has 2 wires (there should be 3 in total). You can connect the stabilizer according to this scheme:

Do-it-yourself relay-regulator manufacturing diagram

At the end of the process, you need to connect the yellow wire from the old regulator to the “+” terminal in order to obtain a constant voltage on the sides of the network. Check the resulting voltage regulator on the scooter. At this point, the process of creating a homemade device can be considered complete.

The relay regulator is a very useful thing and necessary for the normal operation of the moped. However, it requires attention and constant monitoring of its work. Therefore, if the device fails or its performance is unsatisfactory, it is better to replace it with a new one, the cost of which today ranges from 300 to 500 rubles.

Carburetor design (video)

For clarity, we suggest watching a video instruction about the design of carburetors and the principle of their operation:

Knowing the structure of the carburetor and understanding what needs to be connected where, you can easily disassemble, reassemble, clean and adjust it yourself, regardless of what brand and model of scooter you have, with some skill. All these procedures will not take much time and will help you save money on car services. The ability to carry them out will help you out when the engine does not want to start.

Source

Troubleshooting

What to do if the hoverboard does not charge? Here are some simple tips for troubleshooting:

• First, disassemble the hoverboard.

To remove the bottom panel, use a screwdriver or screwdriver with the appropriate bit. This will allow you to get to the inside of the vehicle and try to find the problem of poor charging.

The side of the scooter with the charging port is the area you need to work on. Be careful during disassembly. Do not lose screws or washers, or use a drill to remove screws or bolts that will not come loose. There will be several wires directly on the inside of the plastic cover you just unscrewed.

They are responsible for charging the hoverboard: they connect the charger ports and the lithium-ion battery. The other wire line goes to the motherboard. You can temporarily disconnect it to avoid an unexpected power surge (only if the board is disconnected by a connector). If the wires are soldered, it is better not to touch them.

Is there blackening of the wire or oxidation of the contacts, is there a large amount of dust present? This may well be the reason for the device to not work correctly. Accumulations of dust must be removed, damaged wires must be replaced, and contacts must be cleaned to a metallic shine.

Having completed such an impromptu diagnosis, screw the cover back to the hoverboard, tightening all the removed bolts one by one.

They will help you make diagnostics more efficiently and without risk to the scooter. True, it is no longer free.

If, despite all this, your scooter continues to work incorrectly, you will need to contact the manufacturer and request repair instructions. In the worst case, the hoverboard will have to be sent back to the manufacturer under warranty. It may be that the device was initially faulty and will be replaced under warranty. It often happens that a newly purchased hoverboard does not charge.