2003 Yamaha 70 hp runs rough at lower rpms , runs great at WOT

I have a 70 hp Yamaha that seems to have problems getting it act together unti you hit about 3000 rpms. I just have the carbs rebuilt, new kits etc. , idle adjust set at 1 1/2 turn per the book, etc. and timing set also as per the manual. What I notived the last time I pulled the plugs was that the top cylindar was wet the bottom two were dry or a dry brown in color. I change the top plug but still seemed to be wet when I oulled it. compression is 105 in each cylinder. Aby ideas on why this top cyclindar is running so rich or is possibly fouling the plugs at lower rpms?

Any thoughts appreciated.

Check to see if you have spark that will jump a gap of 7/16" on each cylinder -----Yes 7/16" ---------any thing less may indicate spark problems .---------It sound like you are running on 2 cylinders.