Four-Stroke Engine Mechanics

The video tutorial provides an overview of four-stroke EFI gas engines, detailing their components and the four strokes: intake, compression, combustion, and exhaust. It explains how these strokes work together to power the engine, the role of the crankshaft, and the concept of RPM. The tutorial concludes with a summary of the engine's smooth and reliable operation.

What are the basic components of a four-stroke gas engine?

• Piston, connecting rod, crankshaft

• Battery, alternator, spark plug

• Fuel tank, carburetor, exhaust

• Radiator, fan, thermostat

How is the lateral motion of the piston converted in a four-stroke engine?

• Into a vertical motion at the crankshaft

• Into a static motion at the crankshaft

• Into a rotating motion at the crankshaft

• Into a diagonal motion at the crankshaft

What does the fuel delivery system in a four-stroke engine include?

• Radiator, coolant, fan

• Battery, alternator, starter motor

• Oil pump, filter, dipstick

• Air intake manifold, valves, fuel injector, spark plug

What is the purpose of the intake stroke in a four-stroke engine?

• To ignite the air-fuel mixture

• To draw in air and fuel

• To compress air and fuel

• To release exhaust gases

During which stroke does the spark plug fire in a four-stroke engine?

• Exhaust stroke

• Compression stroke

• Intake stroke

• Combustion stroke

What happens during the exhaust stroke of a four-stroke engine?

• The piston ignites the air-fuel mixture

• The piston draws in air and fuel

• The piston releases the burned air-fuel mixture

• The piston compresses the air-fuel mixture

How many strokes of the piston are needed to create one revolution of the crankshaft?

• One stroke

• Two strokes

• Three strokes

• Four strokes

What does RPM stand for in the context of engine operation?

• Rates per minute

• Rounds per minute

• Revolutions per minute

• Rotations per minute

At wide open throttle, how many times can the crankshaft turn per second?

• 66 times

• 83 times

• 100 times

• 50 times

What are the characteristics of a four-stroke EFI engine?

• Noisy and unreliable

• Smooth, quiet, and reliable

• Slow and inefficient

• Complex and high-maintenance