The specific speed of Dongfa's 4-6 HP outboard engine (MFS6) is affected by a number of factors, including the weight of the vessel, design, hull shape, propeller size and other environmental conditions. However, according to general outboard engine performance data, a 6-horsepower 4-stroke engine is usually able to provide enough power for small boats to reach speeds of about 20-30 km\/h (about 12-18 MPH). This speed range is a rough estimate and actual speeds may vary.