The part in question is the fuel pump & the O-Ring #18 that seals it to the valve cover is the probable cause of the leak.
http://www.boats.net/parts/search/Yamaha/Outboard/2004/T9.9ELRC/FUEL%201/parts.html
Here is the link for everything you need to know Including phn number for questions on returns for repair.
http://www.raymarine.com/view/?id=837
Mon-Fri, 8.15am-5pm (EST)
Raymarine Product Repair Center
9 Townsend West Nashua NH 03063 USA
+1 603 324 7900
[email protected]
Go to edit profile and set your time zone to (GMT -5:00 hours) Eastern Time ( US & Canada ) & check mark: Automatically detect when my timezone is in DST
That should do it for you.