Air-Cooled Engines

May 2, 2012

The new SP Series Engines are a valuable addition to Subaru’s extensive line of air-cooled engines, offering advanced overhead cam (OHC) technology for heightened performance and longevity. Designed for the light commercial and premium residential engine markets, the new engines provide more power and easier starts, while minimizing noise and emissions, making them ideal for use with pressure washers, generators, pumps, go-carts and a variety of lawn and garden equipment. The SP Series includes the SP170, a 5.7-horspower, 169cc displacement engine, and the new SP210 model, a 211cc displacement unit offering 7-horsepower. 

Utilizing a high-performance automotive design, they feature chain-driven OHC technology combined with an efficient hemispherical combustion chamber for optimum engine performance. Intake and exhaust valves are positioned to lower resistance for the air/fuel mixture, while a high compression ratio produces greater power and torque. Sound reduction is often critical when operating equipment near businesses and homes. The SP engines have been designed with fewer moving parts and optimized-capacity rigid mufflers to significantly reduce mechanical noise. As a result, the engines are a full 2dBA (decibel level) quieter and softer in exhaust tone than other same-class engines. Yet another advantage of modern OHC engine technology is starting ease. Because of its optimized combustion chamber design, the SP engines offer easy one-pull starts, with no perceptible kickback. 

An automatic decompression system reduces the required recoil pulling force by 30-40 percent when compared to older overhead valve (OHV) engine designs. Subaru’s patent-pending cooling technology eliminates excessive heat – the primary cause of engine failure – by forcing air over large, slanted cooling fins cast into the mounting base, cylinder and both the interior and exterior crankcase. In addition, the SP engines allow for 360-degree airflow around the intake and exhaust valves, further improving cooling performance and prolonging engine life. Engine life and performance are further enhanced by a precise lubrication system.  Featuring a unique oil scraper that supplies oil to the cam chain and special rocker cover design, the camshaft and rocker arms are continuously bathed in oil to provide lubrication and lower head temperature. Additionally, components like cast-iron cylinder liners, dual ball bearings and high quality piston rings further enhance durability and make the SP engines well-suited for the rugged conditions of the outdoor power equipment industry. 

 The SP Engines comply with EPA emissions regulations and are backed by Subaru’s 3-year warranty on residential and 1-year warranty on commercial applications. 

  • advanced overhead cam (OHC) technology
  • high-performance automotive design
  • automatic decompression system