flat-2 · 0.437 L · petrol · naturally aspirated · air-cooledOMC 437 cc two-stroke twin 1970–1975 The air-cooled, die-cast aluminium two-stroke flat-twin of 437 cc, rated at 25 hp, that OMC supplied for the Cushman Trackster; the owners' description calls it the Johnson snowmobile engine. Electric start, solid-state ignition, single carburettor. 2 vehicles: Trackster Marsh, Trackster