Yamaha 115-225 HP Outboards Service Manual, Page 166Get this manual
5) If the feeler gauge(s) will not fit, then add additional shims until the feeler gauge(s) (set at the specification) just fit between the tool and the gear6) If the feeler gauge(s) are loose fit, then remove shims until the feeler gauge(s) (set at the specification) just fit between the tool and the gearAvailable shim thicknesses: 0.10, 0.12, 0.15, 0.18, 0.30, 0.40 and 0.50 mm
Pinion gear shim 1) Find pinion gear shim thickness (T3) by selecting shims until the specified measurement (M) with the special tool is obtainedSpecified Measurement (M)1.00 mm+P100 mm