2si was an American engine manufacturer located in
Beaufort, South Carolina. The company was a wholly owned subsidiary of the AMW Cuyuna Engine Company, formerly known as the Cuyuna Development Company.[1][2][3][4]
The company acquired a line of two-stroke engines that were originally designed and produced by JLO of
Germany and marketed them under the Cuyuna brand name for
snowmobile and later
ultralight aircraft use. Later Cuyuna formed a subsidiary Two Stroke International, commonly known as 2si, to produce and market the engine line. Cuyuna ended selling engines for aircraft use, but instead switched to marketing them only for industrial, marine,
auto racing,
kart and
all-terrain vehicle applications.[1][5]
The company seems to have gone out of business in 2014.