1983 Yamaha 30EN Outboards Service Manual, Page 111Get this manual
Bearing Model Measurement Bearing models are used in these procedures to avoid having to install and remove the bearings repeatedlyThe width of the bearing models must be compared to that of the new bearings, and the differences, if any, must be accounted for during the shimming procedure1Place the bearing on flat plate, position dial gauge on magnetic stand so that it contacts the outer race, and zero the gauge in that position After pinion position and gear lash have been established, be sure to reverse the action taken in Step prior to installing the actual bearingsDetermining pinion gear position 1Install the original forward gear bearing shims or new shims of the same thickness2Install the forward gear bearing model shims as determined by the bearing model measurement3Place the forward gear bearing model on the gauging plug, install long 8mm bolt in the plug to use as handle, and insert the forward gear bearing model into the gearcaseRemove the bearing, and replace it with the bearing modelNote the difference between the bearing width and that of the bearing model