EX Series engines from Subaru Robin use high-performance, chain-driven overhead cam (OHC) technology in the industrial air-cooled market. Featuring four models with power ranges from 4.5- to 9-hp (3.3- to 6.7-kW), the EX Series offers improved power, faster starting, and quieter operation. Chain-driven OHC technology allows the intake and exhaust valves to be positioned for enhanced engine performance, and it paves the way for lower resistance for the air/fuel mixture flow. A high compression ratio produces higher power and torque while limiting exhaust emissions and fuel consumption. Other benefits include easy starts with no perceptible kickback, automatic decompression system to reduce recoil pulling force by 30 to 40%, fewer moving parts for reduced maintenance, and a redesigned combustion chamber.