Suzuki DF25/DF30 Four Stroke Service Manual, Page 246Get this manual
10-22 LOWER UNIT
TRIM TAB
The trim tab counteracts or minimizes propeller torque "pull" felt through the steering systemIf the steering is pulled to starboard or port side, adjust trim tab with following procedure:
Adjusting 1Loosen the bolt of trim tab2Change the direction of trim tab To compensate for veer to starboard, set trailing edge of tab to the right (as viewed from behind) To compensate for veer to port, set trailing edge of tab to the left3Tighten the bolt of trim tab4Test ride the boat and repeat the procedure to set the trim tab in the best positionWith properly adjusted trim tab, steering should be neutral and there should be no tendency for the steering to be pulled to either port or starboard