2001 Edition Yamaha F225A and LF225A Outboards Service Manual, Page 217Get this manual
Backlash (counter rotation model) 9Turn the shift rod into the reverse position with the shift rod push arm10Turn the drive shaft clockwise until the dog clutch is fully engagedNOTE: When measuring the reverse gear backlash, turn the shift rod push arm towards the reverse position with forceReverse gear backlash: 0.701.03 mm (0.0280.041 in) 15Add or remove shim(s) if out of specificationReverse gear backlash 11Turn the shift rod to the neutral position with the shift rod push arm12Turn the drive shaft counterclockwise approximately 30Less than 0.70 mm (0.028 in) More than 1.03 mm (0.041 in) M: Measurement Available shim thicknesses: 0.10, 0.12, 0.15, 0.18, 0.30, 0.40, and 0.50 mm 16Remove the special service tools, and then install the water pump assemblyShim thickness To be decreased by (0.87 M) 0.71 To be increased by (M 0.87) 0.71