For your consideration is a Yamaha oem Service Manual pdf download:
Manual # LIT-18616-02-86_2005-2010 F90 4-stroke models ---241 pgs
[Yamaha tech pubs...
This Manual Covers All Versions of the Following Machines:
1997 Yamaha 60HP 2-Stroke Outboards
1997 Yamaha 70HP 2-Stroke Outboards
1997 Yamaha 75HP 2-St......