1996-2005 Suzuki DF40, DF50 Four Stroke Outboard Service Manual, Page 75Get this manual
ENGINE CONTROL SYSTEM 3-20 BY-PASS AIR SCREWPASSAGE Since the throttle valve is almost fully closed when idling trolling, the main flow of air necessary to maintain idlingtrolling speed passes through the by-pass air passageThe by-pass air adjustment screw controls the flow of air through the passage and provides means of partially adjusting the total amount of air necessary for idlingtrolling
NOTE: See page 2-14 for the by-pass air screw adjustment procedureIAC VALVEPASSAGE The IAC valve is solenoid plunger type mounted on the electrical parts holderIts purpose is to control the amount of intake air flowing from the IAC passageThe IAC valve is driven by the duty cycle signal from the ECM
IDLE AIR CONTROL SYSTEM