2009 Yamaha F40 Outboard Service Manual, Page 278Get this manual
Shimming
Measuring the forward gear backlash
Spray anti-rust lubricant on the gear and bearings before installationDo not apply gear oil to the partsOtherwise, correct measurements cannot be obtained Keep the parts free from foreign materials, such as dirt or lint When measuring the forward or the reverse gear backlash, use the original bearings and shims Use heat-resistant glovesOtherwise, burns could result To avoid the risk of fire, remove any flammable substances, such as gasoline and oil, around the working area Keep good ventilation while working1Install the original shim(s) (T1)
7Measure the forward gear backlashSee "Measuring the forward and reverse gear backlash before disassembly" (8-25) step 3step 16Forward gear backlash: 0.180.66 mm (0.00710.0260 in)
Adjusting the forward gear shim thickness (T1)
1Remove the taper roller bearing outer raceSee "Disassembling the lower case" (8-13) step 32Measure the thickness of each original shim(s) (T1) in places
Do not reuse shim if deformed or scratched3Determine the forward gear shim thickness (T1) adjustment using the "Forward gear shim (T1) selection chart" according to the truncated average (BL1) from "Measuring the forward gear backlash Example: (BL1)0.10 mm (T1) adjustment0.15 mm from the "Forward gear shim (T1) selection chart The current shim thickness must be decreased by 0.15 mm0 b