What is two stroke and four stroke engine?

A four stroke engine is what is in most cars. It has four steps to make power. Piston goes down for fuel, up to squeeze, down for the bang, and up to push smoke out. So, two turns of the crank for one power push. They are more quiet. They also run more clean because oil is separate from the petrol.

A two stroke is more simple. It does all that in just two steps. One up, one down. So you get a power push for every one turn. This is why they are powerful for their small size. You find them in things like chainsaws and old motorbikes. You must mix oil in the petrol. They are often loud and make more smoke.