Abstract: An air turbine starter containing a liquid lubricant is provided with a passive hydraulic capacitor which is charged by operation of the starter. Charging the capacitor partially drains the lubricant reservoir contained in the starter. This partial drainage decreases drag on internal, rotating components of the starter, thereby decreasing parasitic loss in output torque. The capacitor discharges the lubricant back into the starter when the latter discontinues running, thereby satisfying lubrication requirements of an internal overrunning clutch.