Volvo Penta 5.7 OSI high idle when warm

liuxue2010

I have 2006 Rinker 342.  The starboard engine is around 1000 RPM at idle when day 1 I got it.  so I changed IAC, ignition cable, cap, distributor rotor and sparks but it's still high so I adjust the screw on the butterfly of throttle body.  the idle is good at 650 RPM.  I also took off the throttle cable from throttle linkage because I  would like to make sure there's no any pressure coming from remote control.  I manually push the throttle linkage from the engine and tried 1000, 2000,3000 then go back to idle.  I tried this mode couple times then go back to idle mode.  The engine idle will be raised to 900 or 1000. looks the computer tell IAC to give more air or tell TPS to give more fuel.  The idle will be 650 if I restart the engine but when give more gas and come back to idle a couple time , the idle will be changed to 1000 around, anyone can help?

liuxue2010

Today, I used the scan tool, I also found idle pre-configed to 900 around in ECU when only turn key on without starting engine. once engine started , the scan tool will show idle rpm 600 in ECU.