Internal combustion engine-driven working machine provided with oil lubrication

A tamper for ground-compaction in which the drive motor for the tamper is an internal combustion engine, the tamper comprising:

• a working mass which can be driven linearly in a reciprocating manner by means of the drive motor for the purpose of exerting a tamping or percussive action, and having a tamping or percussion system which is surrounded by an enclosure and in which the rotational movement of the drive motor is converted into a reciprocating linear movement and is transmitted to the working mass, wherein the tamping or percussion system is provided with oil lubrication and the air induction channel of the motor is provided with an air filter, wherein the enclosure which surrounds the tamping or percussion system is provided with a small opening which opens out downstream of the air filter into the air induction channel of the internal combustion engine and whose cross-section is dimensioned so as to enable the equalization of pressure between the tamping or percussion system and a surrounding area and to allow oil to travel from the tamping or percussion system into the air induction channel of the motor.