2-stroke combustion engines are found in a lot of STIHL chainsaws. But some people employ the 4-MIX engine. Thus, the STIHL 4-MIX engine combines the positive aspects of both 2- and 4-stroke engines. The 4-MIX engine is persuasive in terms of decreased pollutants, easy maintenance, and a pleasing sound, in addition to having plenty of hauling power and noticeably increased torque.