An rpm governor for fuel injection engines whose function is to raise the idle rpm for a predetermined time period while the engine is cold in order to guarantee a clean idle running cycle of the engine. The rpm governor includes a compensating device having a thermostat which is designed to engage an idling spring and whose duration of engagement is determined by a heating device located on the thermostat. When the engine is cold, the tension in the spring is raised by the compensating device, thus effecting a higher rpm level, which rpm level is later reduced to normal idle when the governor has reached an operational temperature upon the passage of a predetermined period after cold starting.