2018 Mercury Marine® FourStroke 25 HP EFI A Three-cylinder Performer Crisp handling to keep you moving forward Features may include: Great acceleration / more torque. Compact but powerful, Mercury® 15 - 30hp FourStroke outboards feature extra displacement and outstanding low-end torque that put a boat smartly on plane. Electrical Support. A high-output alternator keeps batteries charged and fishing electronics humming. Dependable starts and performance. Battery-free Electronic Fuel Injection (EFI) on Mercury 25 - 30hp FourStroke models delivers consistently easy starting, crisp throttle response, increased fuel economy and outstanding overall performance.