In a two-stroke engine, how many power strokes occur per crankshaft rotation?

• A. 2
• B. 1
• C. 0.5
• D. 0.25

Answer: (B)

Two-stroke engines complete the entire operating cycle in one turn of the crankshaft, so the combustion event that creates the power stroke happens once with each revolution. For each cylinder, this means one power stroke per crankshaft rotation. The other options would imply more or fewer cycles per turn than the two-stroke design provides (two strokes per turn or fractional cycles), which isn’t how a two-stroke produces power.