The present invention relates to an internal combustion-operated setting tool for driving fastener elements such as nails, bolts, pins into a substrate, having a fuel source, with a fuel feed line from a fuel source to a combustion chamber and having at least one dosing device (30), which is arranged between the fuel source and the combustion chamber. For improving such setting tools, a displacement body (50) is arranged in a chamber in the dosing device (30) for forcing fuel out of the chamber, whose displacement volume can be adjusted.