Overhead cam engine

Subaru’s EX Series engines utilize high-performance, chain-driven overhead cam technology. Featuring four models with power ranges from 4.5 to 9 hp, the EX Series are designed with a highly efficient pent-roof-type combustion chamber, which allows them to utilize a high-compression ratio to produce higher power and torque while limiting exhaust emissions and fuel consumption. An automatic decompression system reduces the required recoil pulling force by 30 to 40 percent when compared with overhead valve engine designs.