A four-stroke engine. / A vehicle or machine powered by a four-stroke engine.

Of or relating to a design of internal combustion engine in which the pistons perform four strokes per engine cycle: intake, compression, power, exhaust.

(automotive) Abnormal operation of a two-stroke internal combustion engine, such that the cylinder only fires every second cycle (like a four-stroke engine). This occurs when the exhaust scavenging and inlet charging leaves a mixture in the cylinder which does not ignite, but needs a second scavenge/charge to produce an adequate mix.

plural of four-stroke engine

An engine that works on the four-stroke principle.