1983 Yamaha 30EN Outboards Service Manual, Page 27Get this manual
Idle speed adjustment 1Turn the pilot screw until it is lightly seatedTurn out the pilot screw to specificationPilot screw (turns out): GEAR OIL Oil level check Remove the oil level plug and check whether the oil level is up to the bottom brim of the holeIf it is not up to this level, replenish oilNOTE: Be sure the motor is positioned straight up when checking the oil level
1Oil level plug
2Oil drain plug
Oil replacement