Subaru’s ER12 Rammer engine features a balanced design intended for the demanding application of rammers. With specially planned components and belt-driven overhead cam (OHC) technology, the 3-hp (2.2-kW), four-stroke ER12 engine weighs just over 20 lb (9 kg) but offers additional power and output than other similar-sized engines. A slim, compact vertical cylinder design maintains its center of gravity to transmit power to the ground, and the recoil is integrated into the flywheel and blower housing to improve balance and engine performance. The ER12 includes a pressure lubrication system; a gear pump transfers oil from the bottom of the crankcase to various parts of the engine that need critical lubrication. Additionally, the belt moves oil to the top of the engine, ensuring all areas are properly lubricated. Other features of the OHC technology include increased power, easy starting, quiet operation, and an efficient hemispherical combustion chamber.