Suzuki DF200/DF225/DF250 V6 4-Stroke Outboards Service Manual, Page 61Get this manual
PERIODIC MAINTENANCE
ENGINE VACUUM CHECK
Engine vacuum is required for proper operation of the Multi-Stage Induction system used on the DF225DF250Engine vacuum is also an indicator of general engine condition1Warm up engine to normal operating temperatureMake sure engine idle speed is within specification2Stop engine and disconnect vacuum outlet hose from PORT side of intake manifold outer cover (collector cover)3Connect special tools (vacuum gauge, hose and 3-way joint) between engine vacuum hose and collector cover hose connection! 09915-67311: Vacuum Gauge 09918-08210: Hose joint 09355-35754-601: Hose 09367-04002: 3-way joint