2001 Edition Yamaha F225A and LF225A Outboards Service Manual, Page 187Get this manual
Shimming (regular rotation model) Selecting the forward gear shims
1Calculate the specified value (M0) as shown in the examples below
NOTE: Measure the taper roller bearing at three points to find the clearance averageNOTE: "F" is the deviation of the lower case dimension from standardThe "F" mark is stamped on the trim tab mounting surface of the lower case in 0.01 mm unitsIf the "F" mark is unreadable, assume that "F" is zero and check the backlash when the unit is assembledCalculation formula: Specified value (M0)0.50 F100 mm Example: If "F" is (+5), then M00.50 (+5)100 mm0.50 0.05 mm0.45 mm If "F" is (3), then M00.50 (3)100 mm0.500.03 mm0.53 mm 2Set the shimming tool on the taper roller bearingShimming gauge 1: YB-06439 3Measure the clearance (M) between the shimming tool and the bearing outer race as shownNOTE: The sum of T1 and M0 should not be more than MCalculation formula: Forward gear shim thickness (T1)M0 Available shim thicknesses: 0.10, 0.12, 0.15, 0.18, 0.30, 0.40, and 0.50 mm 4Select the forward gear shim(s) (T1)