Hey Striper56,
Just in case you don't have this link:
http://www.boatinfo.no/lib/yamaha/ma...003yamaha.html
Section 3 deals with fuel and there are some good write-ups on OX66 EFI engines. On 3-58 and 3-59 there is a discussion on CCS also. The engine only fires on 4 cylinders between 850 RPM and 2000 RPM and 5 cylinders below 850 RPM. There is also a shift cut switch that if actuated (for example by moving the throttle into neutral from WOT) causes the engine to drop two cylinders, no matter what the RPM's are. This is to avoid shock to the drive train.