Podcast
Questions and Answers
A governor malfunction that results in engine speed oscillations is known as ____________.
A governor malfunction that results in engine speed oscillations is known as ____________.
hunting
A carburetor relies on ____________________ in pressure to mix fuel and air and to keep the mixture moving in the right direction.
A carburetor relies on ____________________ in pressure to mix fuel and air and to keep the mixture moving in the right direction.
differences
What is a reservoir containing extra fuel that is drawn into the airstream when the throttle valve is suddenly opened?
What is a reservoir containing extra fuel that is drawn into the airstream when the throttle valve is suddenly opened?
acceleration well
What part of the carburetor increases the speed of airflow and decreases pressure?
What part of the carburetor increases the speed of airflow and decreases pressure?
Signup and view all the answers
At normal engine speed under normal operating conditions, the proper air-fuel mixture ratio is typically ________ parts air to 1 part fuel.
At normal engine speed under normal operating conditions, the proper air-fuel mixture ratio is typically ________ parts air to 1 part fuel.
Signup and view all the answers
The carburetor causes fuel to flow through the main nozzle into the airstream; lowers the boiling point of the fuel, causing some of the fuel to vaporize before it reaches the cylinder; and increases the speed of the airstream, atomizing the fuel leaving the main nozzle when there is a _______________ ________________.
The carburetor causes fuel to flow through the main nozzle into the airstream; lowers the boiling point of the fuel, causing some of the fuel to vaporize before it reaches the cylinder; and increases the speed of the airstream, atomizing the fuel leaving the main nozzle when there is a _______________ ________________.
Signup and view all the answers
What are the three groups carburetors can be categorized into, based on the airflow through the air horn?
What are the three groups carburetors can be categorized into, based on the airflow through the air horn?
Signup and view all the answers
What part of the carburetor is responsible for maintaining a constant fuel level in the float bowl?
What part of the carburetor is responsible for maintaining a constant fuel level in the float bowl?
Signup and view all the answers
If the float springs a leak or becomes saturated and sinks, too much __________ will be provided to the engine.
If the float springs a leak or becomes saturated and sinks, too much __________ will be provided to the engine.
Signup and view all the answers
The purpose of the ____________ is to provide a rich mixture for cold engine starting.
The purpose of the ____________ is to provide a rich mixture for cold engine starting.
Signup and view all the answers
When the throttle valve is completely closed in a natural draft carburetor, most fuel is provided to the engine through the ______________ _______ ____________.
When the throttle valve is completely closed in a natural draft carburetor, most fuel is provided to the engine through the ______________ _______ ____________.
Signup and view all the answers
What kind of carburetor has an integral impulse fuel pump?
What kind of carburetor has an integral impulse fuel pump?
Signup and view all the answers
What kind of carburetor is always mounted on top of the fuel tank?
What kind of carburetor is always mounted on top of the fuel tank?
Signup and view all the answers
These primers increase air pressure in the float bowl, forcing fuel up the main nozzle.
These primers increase air pressure in the float bowl, forcing fuel up the main nozzle.
Signup and view all the answers
As engine load decreases and engine speed increases, a governor with __________ the throttle.
As engine load decreases and engine speed increases, a governor with __________ the throttle.
Signup and view all the answers
What type of governor adjusts engine speed based on the movement of flyweights on the governor gear?
What type of governor adjusts engine speed based on the movement of flyweights on the governor gear?
Signup and view all the answers
Vacuum governors are located between the carburetor and the _____________ ________________.
Vacuum governors are located between the carburetor and the _____________ ________________.
Signup and view all the answers
In an EFI system, what does the MAP sensor send information about?
In an EFI system, what does the MAP sensor send information about?
Signup and view all the answers
The IAT sensor improves the efficiency of a fuel injection system because it sends a signal to the ECU that allows the ECU to make adjustments to the fuel mixture based on ________ ____________________.
The IAT sensor improves the efficiency of a fuel injection system because it sends a signal to the ECU that allows the ECU to make adjustments to the fuel mixture based on ________ ____________________.
Signup and view all the answers
This sensor is used only in closed-loop EFI systems, monitors the chemical composition of exhaust gases, and provides feedback to the ECU that is used to adjust fuel trim.
This sensor is used only in closed-loop EFI systems, monitors the chemical composition of exhaust gases, and provides feedback to the ECU that is used to adjust fuel trim.
Signup and view all the answers
Delivers fuel to the venturi when the engine is operating at speeds above idle.
Delivers fuel to the venturi when the engine is operating at speeds above idle.
Signup and view all the answers
What restricts airflow into the carburetor to enrich the air-fuel mixture?
What restricts airflow into the carburetor to enrich the air-fuel mixture?
Signup and view all the answers
What reduces air pressure in the float bowl when the engine is operating at part throttle?
What reduces air pressure in the float bowl when the engine is operating at part throttle?
Signup and view all the answers
What regulates the amount of air-fuel mixture entering the cylinder?
What regulates the amount of air-fuel mixture entering the cylinder?
Signup and view all the answers
What increases air velocity and reduces pressure by restricting the carburetor's air passage?
What increases air velocity and reduces pressure by restricting the carburetor's air passage?
Signup and view all the answers
What maintains a constant fuel level within the carburetor?
What maintains a constant fuel level within the carburetor?
Signup and view all the answers
What provides additional fuel when airflow through the carburetor is maximized?
What provides additional fuel when airflow through the carburetor is maximized?
Signup and view all the answers
What delivers a small amount of air-fuel mixture to the cylinder when the throttle valve is closed?
What delivers a small amount of air-fuel mixture to the cylinder when the throttle valve is closed?
Signup and view all the answers
Study Notes
Carburetor Terminology
- Hunting refers to engine speed oscillations caused by a governor malfunction.
- A carburetor relies on differences in pressure to mix fuel and air appropriately.
- The acceleration well is a reservoir that provides extra fuel when the throttle valve opens suddenly.
- The venturi section of a carburetor accelerates airflow while decreasing pressure.
Fuel-Air Mixture
- The ideal air-fuel mixture ratio at normal engine speed is typically 15 parts air to 1 part fuel.
- Fuel vaporization is enhanced by pressure reduction in the carburetor, allowing better atomization.
Carburetor Types
- Carburetors can be grouped by airflow type: natural draft, updraft, and downdraft.
Carburetor Components
- The float maintains a constant fuel level in the float bowl; a malfunction can lead to excessive gas delivery.
- Choke mechanisms enrich the fuel mixture for cold starts.
- The primary idle orifice supplies fuel when the throttle valve is closed in a natural draft carburetor.
- Diaphragm carburetors have an impulse fuel pump integrated within.
Engine Management
- Vacuum carburetors are typically placed atop the fuel tank.
- Dry bulb primers function by increasing air pressure in the float bowl, pushing fuel into the main nozzle.
- Governors operate by adjusting the throttle as engine load and speed change.
Sensors and Fuel Injection
- The MAP sensor in EFI systems monitors intake airflow and relays data to the ECU.
- The IAT sensor adjusts fuel mixtures based on air temperature, improving EFI efficiency.
- The O2 sensor in closed-loop EFI systems provides feedback on exhaust gas composition to adjust fuel trim.
Fuel Delivery Systems
- The main discharge nozzle delivers fuel to the venturi during high engine speeds.
- The choke system limits airflow to create a richer air-fuel mixture.
- The economizer circuit reduces float bowl pressure during part throttle operation.
- The throttle system manages the air-fuel mixture entering the engine's cylinders.
Additional Systems
- The float system ensures a stable fuel level in the carburetor.
- The acceleration system provides extra fuel under maximum airflow conditions.
- The idling system maintains a consistent air-fuel mixture when the throttle valve is closed.
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Description
Test your knowledge on carburetor functions and terminology with this quiz. Each question is designed to help reinforce your understanding of key concepts important in small engine technology. Ideal for students and enthusiasts alike.
