A belt tensioning device (10) prevents excess belt tension when installing a belt (16) between a driver axis (28) and a spindle axis (22). A clutch (48) supported on a fixed structure (14, 46) includes an engagement member (52, 64) and a rod (32). Rotating the engagement member (52, 64) in a first direction moves the rod (32) and the driver axis (28) in a direction away from the spindle axis (22), until further rotation causes the engagement member (52, 64) to disengage preventing further movement of the driver axis (28) in the direction away, and subsequent rotational movement of the engagement member (52, 64) in a second rotational direction moves the driver axis (28) toward the spindle axis (22).