A sudden failure when trying to overtake on the highway or the inability to accelerate the car above a certain speed often indicates incorrect operation of the mixture enrichment system in the carburetor Solex. Exactly power mode economizer (EMR) is responsible for supplying additional fuel when the throttle valve is opened sharply, and its failure turns a dynamic car into a slow-moving vehicle with a jerky character. Unlike idling, where the mixture must be leaner to save money, full load mode requires a sharp increase in the supply of gasoline, which is implemented by this unit through a special channel and valve.
Structurally, the system consists of a membrane mechanism connected to the throttle valve and a separate fuel channel with a nozzle leading into the mixing chamber. When you press hard on the gas, the throttle valve opens, creating a vacuum that acts on the economizer membrane through a system of channels. If this process is disrupted, the engine begins to “choke” due to the leanness of the mixture at the moment when, on the contrary, it needs the maximum amount of fuel for combustion.
Owners of VAZ cars equipped with carburetors 21083, 21073 or 21081, must understand that EMR malfunction is often disguised as problems with the ignition system or clogging of the main fuel jets. However, diagnosing this particular unit requires a specific approach, including checking the tightness of the membrane, the condition of the ball valve and the channel capacity. Ignoring the symptoms of economizer failure leads not only to loss of dynamics, but also to engine overheating due to running on a lean mixture under load, which can lead to valve burnout.
Operating principle and design of the economizer
Operation power mode economizer is based on the pressure difference in the intake manifold and the float chamber. In normal mode, during smooth driving or idling, the throttle valve is closed and the vacuum under it is high. This vacuum is transmitted through the channel to the diaphragm mechanism, pressing the diaphragm and holding the ball valve in the closed position. Fuel does not flow through the economizer channel into the atomizer, which allows the engine to operate economically.
The situation changes dramatically when the throttle is opened suddenly, for example when overtaking or going uphill. The throttle closes the channel for supplying vacuum to the membrane mechanism, the pressure is equalized, and under the action of the spring the membrane rises. This movement opens the ball valve and additional fuel from the float chamber rushes through economizer jet directly into the mixing chamber, enriching the mixture to the required ratio.
It is important to note that in carburetors of the family Solex The system has its own characteristics compared to Ozone. Here, a two-stage opening of the throttle valves is used, and the economizer is activated precisely in the second chamber or at a certain stroke of the primary valve, depending on the modification. Violation of the geometry of the drive levers or wear of the rod can lead to premature or delayed operation of the system, which immediately affects the traction characteristics of the motor.
⚠️ Attention: An attempt to regulate the operation of the economizer by bending the levers without understanding the physical processes can lead to excessive fuel consumption of up to 30% and the appearance of black smoke from the exhaust pipe.
Typical symptoms of EMR malfunction
Diagnostics begins with an analysis of the vehicle's behavior on the road. If you notice that the car confidently picks up speed up to 60-80 km/h, and then a “failure” begins or the speed stops increasing, despite the gas pedal being fully depressed, this is a classic sign of a non-working economizer. At this moment, the engine operates only on the main metering system, which does not have enough throughput for high speeds.
The second obvious symptom is unstable operation of the engine under load, accompanied by popping noises in the muffler. Popping sounds indicate that the unburned mixture in the cylinders is burning out in the exhaust tract, which occurs due to a critical depletion of the mixture at the moment the throttle is opened. There may also be a decrease in maximum speed and an increase in acceleration time, which is especially noticeable in a loaded vehicle.
There is also the opposite problem - when the economizer “flows” constantly. This occurs if the ball valve does not hold pressure or the membrane is torn and does not block the channel. In this case fuel consumption increases sharply, the spark plugs become covered with black soot, and thick black smoke pours out of the exhaust pipe. The engine may start poorly when hot due to the mixture being over-rich.
- 🚗 A sharp drop in power when sharply pressing the accelerator pedal in high gears.
- 💨 The appearance of black smoke from the exhaust pipe and the smell of unburned gasoline.
- 📉 Inability to reach the maximum speed declared for this car model.
- 🔥 Engine overheating when driving at full load due to a lean mixture.
Diagnostics of the membrane mechanism and channels
Checking the integrity of the membrane is the first step in troubleshooting. To do this, you need to remove the carburetor cover and carefully remove the economizer assembly. Visually inspect the rubber diaphragm for cracks, tears, or loss of elasticity. Even a microscopic rupture will cause the system to stop creating the necessary vacuum, and the valve will not open at the right time.
Next, the mobility of the stem and ball valve is checked. The stem should move freely, without jamming, and the ball should tightly overlap the valve seat. Often the cause of failure is not the membrane itself, but contamination of the vacuum supply channel or sticking of the ball with resinous deposits. Blowing the channel with compressed air and cleaning with a solvent often returns the unit to operability.
Particular attention should be paid to the condition of the valve spring. If it is loose or broken, the valve may open too early or may not close completely. Compare its length and stiffness with a reference spring from a working carburetor. Also check the channel in the carburetor body leading to the sprayer - it should not be clogged with dirt or aluminum oxides.
☑️ Checking the EMR unit
Setting up and adjusting the system
Adjusting the economizer of power modes on carburetors Solex often comes down to correctly installing the jets and checking the timing of the valve opening. The main setting parameter is economizer jet, which is selected according to engine size and driving style. Standard values may not be suitable for high-performance engines or engines with modified valve timing.
To accurately adjust the timing of operation, you must ensure that the throttle valve actuator is operating correctly. The gap between the drive lever and the economizer rod must be such that the opening occurs precisely in the second phase of throttle opening. Opening too early will lead to rushing and overspending, and failure later.
In some cases, it is necessary to adjust the fuel level in the float chamber, since the efficiency of all metering systems, including the economizer, depends on it. If the level is too low, the economizer may suck in air; if it is high, there will be constant overflow. The optimal level is checked in a transparent tube screwed in instead of the drain screw.
⚠️ Attention: Before any adjustment, make sure that there is no debris in the float chamber that could get into the thin channels of the economizer and interfere with its operation.
Subtleties of jet selection
For naturally aspirated engines with a volume of 1.5-1.6 liters, economizer jets with a diameter of 40-45 are usually used. For engines 1.7 liters and above, as well as for cars with turbocharging, it may be necessary to install larger diameter jets (up to 50-55) to ensure sufficient enrichment of the mixture.
Table of standard jets and parameters
When replacing or selecting components, it is important to focus on the factory specifications for a specific carburetor modification. Below is data for the most common models that will help you determine whether your car has a standard economizer jet or it was replaced by the previous owner.
| Carburetor model | EMR jet diameter | Engine type | Note |
|---|---|---|---|
| 21083 | 40 | 1.5 l (VAZ-21083) | Basic equipment |
| 21083-1107010-31 | 45 | 1.5 l (VAZ-21213) | For Niva, enriched mixture |
| 21073 | 45 | 1.7 l (VAZ-21213) | Enlarged diffuser |
| 21081 | 35-40 | 1.1 l (VAZ-21081) | Small engine capacity |
Using a jet with a smaller diameter than required will lead to operation on a lean mixture in power mode, which is dangerous for the piston group. Installing a jet that is too large will cause overflow and loss of throttle response due to over-richness. Replacing the economizer jet is the easiest and most effective way to tune a Solex carburetor to improve acceleration dynamics.
A properly selected economizer jet can improve a vehicle's acceleration by 10-15% without significantly increasing fuel consumption in the urban cycle.
Frequently asked questions (FAQ)
Is it possible to drive with a faulty power economizer?
You can drive, but it is highly not recommended. Prolonged operation of the engine on a lean mixture under load leads to overheating of the combustion chamber, burnout of the exhaust valves and pistons. In addition, the car loses dynamics, which makes overtaking on the highway unsafe.
How often do you need to clean the economizer channels on a Solex carburetor?
It is recommended to carry out preventive cleaning every 20-30 thousand kilometers or every time you replace fuel filters. If you use high-quality gasoline and good filters, the interval can be increased to 50 thousand km. However, at the first sign of leaks, cleaning should be done immediately.
What is the difference between Solex and Ozone economizer?
The main difference is the drive design and installation location. On Ozones a pneumatic drive with a more complex channel system is used, and Solexakh - mechanical or combined with direct connection to the throttle of the second chamber. The jets and calibrations are also different, so direct replacement of components is not possible without rework.
Why did black smoke appear after replacing the economizer jet?
Black smoke indicates that the mixture is over-rich. Most likely, the jet is too large for your engine size and current carburetor setting. It is necessary to return the standard jet or select an intermediate option, and also check the fuel level in the float chamber.