Merc 200 efi vibration

[elpez]

I'm running a 200 efi merc on my 21 1998 seacraft, the noise and vibration is too much, after 2-3 hours on the boay I'm ready to swim home. Its worse at 3500- 4000 rpm but noticeable at idle too, engine readily revs up to 4800 without problem and boat planes quickly. Any suggestions??