1998 Yamaha 25J, 30D, 25X, 30X outboards Factory Service Manual, Page 104Get this manual
ASSEMBLY AND ADJUSTMENT
4U sin fe eler es set at th sp ecifie asure nt (M) esta blish e, ch eck th fit et th shi in and th re erse arF orce th shi in ainst th shi and thrust ash er ch eckin th fit5If th fe eler e(s) ill ot fit, th ditio al shi ntil th fe eler e(s) (set at th sp ecificatio n) just fit et th to ol and th ar6If th fe eler e(s) are lo ose fit, th re shi ntil th fe eler e(s) (set at th sp ecificatio n) just fit et th to ol and th arAvailable shim thicknesses: 0.05, 0.08, 0.12, 0.30, and 0.50 mm