2006-2010 Suzuki DF150 / DF175 4-Stroke Outboards Service Manual, Page 84Get this manual
ENGINE CONTROL SYSTEM
BY-PASS AIR SCREWPASSAGE Since the throttle valve is almost fully closed when idlingtrolling, the main flow of air necessary to maintain idlingtrolling speed passes through the by-pass air passageThe by-pass air screw controls the flow of air through the passage and provides means of partially adjusting the total amount of air necessary for idlingtrollingNOTE: See page 2-16 for the by-pass air screw adjustment procedureIAC VALVEPASSAGE The IAC valve is stepper motor type mounted on the intake manifoldIts purpose is to control the amount of intake air flowing from the IAC passageThe IAC valve consists of stepper motor, rod, valve and other partsAs the stepper motor is controlled by signals from the ECM, valve position changes will increase or decrease the air flow through the IAC passage
2 1Throttle body 2By-pass air screw