2006-2010 Suzuki DF150 / DF175 4-Stroke Outboards Service Manual, Page 123Get this manual
ENGINE CONTROL SYSTEM
VSV (Vacuum switching valve) 1With ignition switch OFF, disconnect connector from VSV2Check resistance between VSV terminalsResistance of VSV: 37 44
3Disconnect two hoses from VSV4With 12 applied between the VSV terminals, check that port (E) connects to port (F) but not to the filter section5Without voltage applied to the VSV terminals, check that port (E) connects to the filter section but not to port (F)