Suzuki DF200/DF225/DF250 V6 4-Stroke Outboards Service Manual, Page 88Get this manual
ENGINE CONTROL SYSTEM
AIR INTAKE COMPONENTS
Air, after entering through the silencer case, passes through the throttle bodies and flows into the collector assembly (surge tank) where it is then distributed to the cylinder intake manifoldCollector assembly (surge tank) pressure, monitored by the MAP sensor, is an indirect measure of the intake air amountWhen the throttle is fully closed, the main supply of collector assembly (surge tank) air necessary to sustain engine idle passes through the by-pass air passageTo maintain engine idle speed at specification, the ECM controlled IAC valve supplies regulated amount of additional air through the IAC (idle air control) passage3 Air flow 1PORT throttle body 2STBD throttle body 3IAC valve 4By-pass air screw 5Collector assembly 6Throttle position sensor 7MAP sensor 8IAT sensor 9Air intake silencer