Yamaha Marine Outboards Factory Service / Repair/ Workshop Manual 225G 250B L250B, Page 221Get this manual
SHIMMING (COUNTER ROTATION MODELS) (EXCEPT FOR USA AND CANADA)
(2) Calculate the forward gear shim thickness (T2)Forward gear shim thickness (T2)6.50R100 A100 M5M6 NOTE: "R" is the deviation of the lower case dimension from standardIt is stamped on the trim tab mounting surface of the lower case in 0.01-mm units If the "R" or "A" mark is missing or unreadable, assume "R" and "A" value of "0", and check the backlash when the unit is assembled If the "R" or "A" mark is negative (), then subtract the "R" and "A" value from the measurementExample: If M5 is "19.90 mm", M6 is "14.80 mm", is"+7" and is "5", then T26.50(+7)100 (5)100 19.9014.80 mm6.500.070.05 19.9014.80 mm1.52 mm (3) Select the forward gear shim(s) (T2)Calculated numeral at 1100th place More than 0.00 0.02 0.05 0.08 or less 0.02 0.05 0.08 0.10 Rounded numeral 0.02 0.05 0.08 0.10