Small Gas Engine Quiz

Explanation
Three-tyre vehicles do not use small gas engines. The other options, such as all-terrain vehicles, scooters, and motorcycles, typically use small gas engines for propulsion. However, three-tyre vehicles, which are uncommon and usually refer to vehicles with two wheels in the front and one in the back, often use electric motors or larger engines for power instead of small gas engines.

Explanation
The maximum power of small gas engines is typically measured in horsepower. Among the given options, 15 horsepower is the highest value, indicating that it is the maximum power output for small gas engines.

Explanation
Grinders do not have a 2-stroke design. Unlike string trimmers, chainsaws, and concrete mixers, grinders typically use a 4-stroke design. A 2-stroke engine completes a power cycle in two strokes of the piston (one up and one down), while a 4-stroke engine completes a power cycle in four strokes (intake, compression, power, and exhaust). Grinders usually require more power and precision, which is why they typically use a 4-stroke engine for better performance and control.

Explanation
The minimum piston displacement of small gas machines is 25 cc. This means that the piston in these machines has a minimum volume of 25 cubic centimeters. The piston displacement is an important specification for gas machines as it determines the power output and efficiency of the machine. A larger piston displacement generally indicates a more powerful machine. Therefore, in this case, the correct answer is 25 cc.

Explanation
Recoil starters are used as a tool for starting small gas engines. Recoil starters, also known as pull-starts or manual starters, are a mechanism that uses a rope or cord to manually rotate the engine's crankshaft and start the engine. This is a common feature in small gas engines such as those found in lawnmowers, chainsaws, and other handheld power tools. Unlike starter motors, alternators, or batteries, recoil starters provide a simple and efficient way to start these engines without the need for external power sources.

Explanation
The governor is responsible for regulating the engine speed in small gas engines. It is a device that monitors and controls the amount of fuel entering the engine, ensuring that the engine runs at a consistent speed regardless of the load. The governor adjusts the throttle valve or fuel flow to maintain a steady RPM (revolutions per minute) and prevent the engine from running too fast or too slow. This helps to maintain the optimal performance and efficiency of the engine.

Explanation
A fuel pump is not a part of a typical small gas engine. Small gas engines usually rely on a gravity-fed fuel system, where the fuel flows from the fuel tank to the carburetor without the need for a fuel pump. The guide bar is a part of a chainsaw, the oil hole is used for lubricating the engine, and the drive mechanism is responsible for transferring power from the engine to the wheels or blades. However, a fuel pump is not necessary in this type of engine.

Explanation
In 1884, the first electrical igniting device for gas engines was patented. This invention marked a significant advancement in engine technology, as it provided a more efficient and reliable method of igniting the fuel. Prior to this, gas engines relied on other methods such as flame ignition or hot-tube ignition. The introduction of the electrical igniting device revolutionized the industry and paved the way for further developments in engine design and performance.

Explanation
The correct answer is Spring tension. Spring tension refers to the force exerted by a stretched or compressed spring. In a small gas engine, the spring tension is responsible for controlling various components such as the throttle, governor, or valve mechanisms. It allows for the precise regulation of fuel flow and engine speed, making it an essential elastic part of the engine.

Explanation
Torsion springs are absent in small gas engines. Torsion springs are designed to store mechanical energy when twisted, and release it when the torque is released. They are commonly used in applications where rotational force is required, such as in garage doors or clothespins. However, small gas engines typically do not require this type of spring for their operation, as they rely on other mechanisms for generating power and movement.