Abstract: A power drive riding type lawn mower having a manual and automatic lateral/angular movement of the mower deck to provide an object tracing capability. The tracer mower deck arrangement enables moving the deck horizontally and laterally in a direction perpendicular to the frame of the mower and at an angle with respect to the mower frame. A manual lever moves the mower deck transversely and laterally with respect to the mower frame, while an automatic deck positioning lever has numerous transverse positions and once set in a position, the mower deck can be moved laterally and angularly automatically by contact with an object and then returned to that set position. Also, a deck movement override mechanism provides an added safety feature which enables the mower deck to be secured and the automatic trace feature disabled.