We've got manuals for all Mercury / Mariner /Yamaha covering everything from 4hp to 200hp available for download
Boating Resources
They yamaha manual in at the bottom of list on that page - it is a combined book of all Merc/Mariner/Yamaha, 125Mb to download.
I think the wiring diagram you're looking for is on page 365 - only a 115 EFI, but the wiring loom is probably the same.
Hope this helps
Will