Yamaha Marine Outboards Factory Service / Repair/ Workshop Manual 225G 250B L250B, Page 214Get this manual
SHIMMING (COUNTER ROTATION MODELS) (FOR USA AND CANADA)
(2) Install the bearing retainer 1, thrust bearing 2, and shim(s) 3NOTE: If the original shim(s) is unavailable, start with 0.50-mm shim(3) Measure the specified measurement (M)2Adjust: Shim thickness (T1) Remove or add shim(s)Available shim thickness 0.10, 0.12, 0.15, 0.18, 0.30, 0.40 and 0.50 mm NOTE: (M0) (M) should be as close to "0" as possible