Idle Speed Adjustment

I have a 2004 250 HP 2 stroke Yamaha outboard- Z250TXRC. I need to lower the idle speed from 1000 RPM to 700 RPM. Can anyone detail how I can lower my idle speed. Is it a mechanical change ie a screw or is it a electronic adjustment??? Thanks in advance for your help.

[boats.net]

You have to do the synchronization and then adjust the idle speed screw until you get a .62 volt reading on TPS. No further adjustments can be made on idle screw, if engine still doesn't idle at about 750 rpm's then need to put on computer diagnostic to check all sensors.