How 2 Stroke Motors Work

As early as 1880, two stroke engines were invented as a reliable and inexpensive source of power. Although they are a lighter, more powerful engine, they do not last as long and are not very fuel efficient compared to the four stroke engine.

• The term “stroke” means the action of the piston in the engine. In the working of a two-stroke engine the piston makes two “strokes” – one in each direction – for the production of power. The first is a compression stroke that is ignited by the spark and then on the return stroke a new mix of fuel enters the cylinder so the process can be repeated over and over.


• The difference between a two-stroke engine and a four stroke is that the four stroke engines have a full compression stroke, a full exhaust stroke and a return stroke for each of those – hence the term “four stroke."


• Two-stroke engines - due to firing once during each revolution - have more power than four stroke engines. They are also lighter and cost less to manufacture than do four strokes. This is due in part to the fact that most of them do not have valves resulting in simplified construction costs.


• Some drawbacks to two-stroke engines are that due to the increased use of the engines they don’t last quite as long. Their lack of a lubrication system wears the parts out more quickly. The fact that they use an oil/fuel mix means the use of more oil in power production making it more costly. Fuel efficiency is less than in a four-stroke engine. Lastly these engines produce more pollution due to the fact that they actually burn oil in the producing of power.