A two stroke engine fires every time the piston comes to the top of its stroke. They turn faster and have more overall power. they are simpler and cheaper.

A four stroke engine fires every other time the piston comes to the top. It tends to have more low end torque, run a little slower and is more fuel effecient than the two stroke. The four stroke has valves in the cylinder head like your car

They both use the same fuel and field equipment.