PERIODIC MAINTENANCE Every 250 Hours of Operation Every 500 Hours of Operation Perform the following maintenance every 250 hours of operation. Inspecting and / or Replacing the Cone-Clutch Inspecting and / or Replacing the Cone-Clutch See your authorized Yanmar dealer or distributor for procedure. Changing the Lubricating Oil (SD50, SD50-4T) Inspecting and Replacing the Clutch Shifter Changing the Lubricating Oil (SD50, SD50-4T) See Draining and Replacing Lubricating Oil - SD50 / SD50-4T on page 40 . Inspecting and Replacing the Clutch Shifter See your authorized Yanmar dealer or distributor for procedure. SD Operation Manual 49 © 2009 Yanmar Marine International