2006-2010 Suzuki DF150 / DF175 4-Stroke Outboards Service Manual, Page 91Get this manual
ENGINE CONTROL SYSTEM
OCV (Oil Control Valve) The OCV is used to regulate oil flow and is installed on the lower camshaft housingRETARD OPERATION When the duty ratio of the ECM is small, the OCV spool valve is pushed away from the coil by spring force and engine oil pressure is applied to the retard chamberEngine oil remaining in the advance chamber is drained out through the spool valveRetard operation Advance chamber Engine oil pressure Drain Retard chamber