The spring marked with code K 72138 supports the function of the flexible rod K 72135 by providing tension and ensuring its return to a neutral or resting position. This spring is critical in systems where precise control of mechanical motion is required, such as in fuel regulation or lubrication delivery. Its resilience under thermal and mechanical stress ensures long-term reliability, making it an important component for the safe and efficient performance of the Sulzer ZV40/48 engine.