1990 Johnson Evinrude "ES" 60 thru 70 Service Manual, P/N 507873, Page 204Get this manual
Trim Tab AdjustmentAll Models The boat may be slightly easier to steer in one direction or the other due to steering forces or other reasonsTo check this, run the boat in straight line with balanced load in an area where current and wind will not be factor
INote single trimset ofadjustment will only relieveconditionsNo tab steering effort under one speed, trim and loading
single setting can relieve steering effort under all speed, trim and loading conditions1Turn the steering wheel in both directions to determine the direction that requires the least amount of steering effort2Loosen the trim tabIf the boat pulls to port, move the rear of the trim tab to port pulls to starboard, move the rear of the trim tab to starboard