Problems w/ Yamaha OX66 250HP

[TwoWisemen]

A little update:
Compression on all cylinders is between 101 and 105 psi. Even though they are all w/in 10%, is this low?

I took the O2 sensor out, soaked it in seafoam up to the threads, scrubed it with a toothbrush, and blew it out with compressed air.

All new sparkplugs. Still runs rough until 3200 rpm. I think before I spend more replacing parts that may or may not be bad, I'm going to take it to the mechanic.