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:
1999 YAMAHA F75 75HP 4-STROKE OUTBOARDS
1999 YAMAHA F80 80HP 4-STROKE OUTBOARDS
1999 YAMAHA...