The invention relates to a percussion tool having an internal combustion engine and a hammer mechanism that can be driven by the internal combustion engine by means of a transmission. A part of the engine housing, the transmission housing, or the impact hammer mechanism housing is enclosed by a cover. The cover is spaced at a distance from the remainder of the machine, so that a gap is present between the cover and the remainder of the machine. Cooling air can flow into the gap at the lower face of the cover and flow back out via a flue and an opening. The components beneath the cover are thereby effectively cooled, even without an additional cooling air blower.