Which of the following is NOT a stroke in the four-stroke cycle?

In a four-stroke engine cycle, there are specifically four distinct strokes that contribute to the overall operation: the intake stroke, compression stroke, power stroke, and exhaust stroke. Each of these plays a critical role in the engine's performance.

The power stroke occurs after the combustion of the fuel-air mixture, producing the energy needed to drive the engine. During the intake stroke, the engine draws in this mixture, while the exhaust stroke expels the burnt gases after combustion. The omission of one of these strokes would disrupt the engine's cycle, so all strokes must be present and accounted for in the four-stroke process.

The term "fuel stroke" is not recognized as one of the four strokes in this cycle. In the context of small engine technology, it does not represent an actual phase of operation but may be mistakenly associated with the intake stroke where fuel is indeed involved. Thus, identifying the "fuel stroke" as not belonging to the four-stroke cycle is accurate; it clarifies that terminology is essential in understanding engine mechanics.