What is a 2 cycle engine?

Answer 1

As the name suggests a two stroke engine achieves in two strokes what a four stroke engine achieves in four strokes.

There are four stages in the cycle of both engines. These are;

Induction

Compression

Power

Exhaust

In a four stroke engine these are separated into individual strokes of the piston.

In a two stroke engine they are combined into 2 strokes as opposed to four by arranging ports and valves in a certain manner.

Two stroke engines are generally lighter than four stroke and run at a higher speed. Though this is not always the case

The two-stroke engine uses fixed intake and exhaust ports which are covered/uncovered by the up-and-down motion of the piston. The piston has only two strokes to a cycle, compression and power, the intake and exhaust being taken care of by the normal motion of the piston. Two stroke engines does not have an oil sump and an oil pump, their lubrication needs are met by the oil being mixed with the gasoline. Therein is their inherent problem: They are very pollutive. Their advantage is a tremendous amount of power-per-pound, as much as 80% more than a four stroke engine of comparable horsepower. There most common use in in applications where a maximum amount of power is needed in the smallest and lightest package, such as chain saws and outboard boat motors.