CDI M.E.D.S. Johnson Evinrude Add-On M.E.D.S., Marine Engine Diagnostic System, is an easy-to-use advanced software package specifically developed for troubleshooting marine engines. ; Benefits from M.E.D.S. Reduce Debug Time; Improve Accuracy; Run & Print M.E.D.S. check report.; Product Description: M.E.D.S. Johnson Evinrude Add-On; Adds Compatibility with Select Johnson Evinrude Engines;