Automobile Choke – Main Definition

Last Updated on January 23, 2023 by Leepu Da Maxim

An automobile choke is a type of mechanical device that controls the air-to-fuel ratio in the carburetor of a gasoline engine during cold starts. It ensures the most appropriate ratio between the amount of air entering and mixing with the fuel.

Key Takeaways

  • You will find the automobile choke mostly in aspirated engines
  • An automobile choke enriches the fuel mixture and helps the engine to start properly in the cold weather
  • The automobile choke is designed to allow for the proper air-to-fuel ratio for normal operation

Automobile Choke – Main Aspects To Consider

Main operationIt is a valve that allows the correct amount of air to enter to mix with the fuel
Temperature Sensor SpringWhen this component detects a low temperature in the engine this valve remains closed
MalfunctionWhen the engine is cold and the valve remains open, this is an improper operation
Cleaning MaintenanceA cleaning may be the solution for the correct operation of the valve
Power ReductionWhen the engine is hot and the valve is closed, power reduction may occur

When Should I Choke The Car Engine?

The choke is one of the most important parts for the correct operation of the engine as it is the valve that closes and opens and works together with the air. So, this valve allows a certain precise amount of air to enter the engine and mix with the fuel. In this way, a certain efficient mixture between air and fuel can be obtained.

In turn, this valve is located before the throttle and works in combination with other engine components. This valve is often very useful when it comes to starting an engine at a low temperature. Of course, in these cases, this valve must remain completely closed to limit and obtain the precise amount of air that must enter the engine.

In this way, the engine will have a better performance to obtain the right temperature. The amount of air can be optimized to mix with the fuel in the cylinder. In other words, the amount of fuel can be increased to obtain a much more balanced mixture. 

Also, a temperature-sensing spring is needed to be able to detect when the engine is already at the right temperature. So, in these cases, the valve can be opened very slowly. When this happens, it means that the engine can breathe as before, and more air can enter the engine.

In case of some problems when starting a vehicle, it is necessary to check this valve inside the engine. Some problems are very common when trying to start a car on a very cold morning. In these cases, this valve may not close completely. So, when this happens, cold starting cannot take place.

There will be too much air in the cylinder and the mixture will not be sufficient to produce the combustion that will ignite the vehicle. Besides, a power reduction may be noticed when this valve does not open fully. In this case, it may be the exact opposite problem and the air inside may be too little. To avoid this problem, here are some easy steps to take. 

1. Checking The Throttle In The Morning

In this case, it is necessary to wait until the next morning to check the proper functioning of this valve. This is the most appropriate time since the low temperature can help to detect more efficiently the functioning of this component.

Here, it is necessary to remember that this valve works together with the temperature sensing spring. So, this valve should be completely closed if the engine is cold.

2. Removing The Air Filter

All vehicles have an air filter, although the design may vary from one vehicle to another. However, it is necessary to find the air filter to remove it. Along with this, the housing must also be removed to gain access to the carburetor. In most cases, people will need some particular tools here.

Of course, a single wingnut is usually used to secure the housing and air cleaner. Many times this nut can be removed without the need for any tools. If you need to, you can opt for some type of wrench to remove this nut and continue with the procedure.

3. Checking The Valve

You will be able to see the first butterfly valve after you have removed the housing and air filter. The first butterfly valve you manage to visualize should be closed. As mentioned, this valve must remain closed because the temperature-sensing spring detects or should detect a low engine temperature.

4. Step On The Throttle

To close the valve properly, you must step on the accelerator pedal several times. Of course, this must be done in case the throttle valve is open instead of closed with the engine cold. You may also need someone to move the lever forward if the car has a manual choke. 

This will enable you to check whether the lever moves back and forth correctly. In this sense, it is a matter of checking whether the valve can move and close as it should.

5. Moving The Valve

When the throttle valve can neither close nor open it is necessary to make some movements. Here, there could be some kind of obstacle that prevents the valve from working properly. The most common is that some dirt has accumulated if it is a car that is a few years old.

It could also be that the temperature sensing adjuster is malfunctioning. Either way, you will be able to use a carburetor cleaner on the valve and clean out all the existing dirt.

Either way, the carburetor cleaner will get into the engine. You should not worry about it and therefore continue until the last particle of dirt is cleaned out. If the valve can close efficiently it is necessary to put the housing back on the carburetor or next to the air filter.

6. Starting The Engine

Finally, it is necessary to start the engine as usual until the temperature is the most appropriate. Once the check and the complete cleaning mentioned above have been carried out, the valve should be working properly. Inspecting the valve also allows a good opportunity to check inside the carburetor.

If you have some extra time it is a good way to take advantage of the minutes and apply a complete cleaning to the carburetor. This should not be optional if you want the carburetor to function correctly and properly.