AT wide open throttle i am getting a condition on my yama 225 hpdi VZ225TLR

The duplication
WOT
RPMS drop about 300 and come back and drop and come back

no water in fuel
Fuel Filter was dirty so we are checking that

WOT also only delivers me about 56oo rpms and that is low also

Jackplate is about 3"BP
Turning a 26p out of box tempest plus
198Elite Champion

May have a little too much pitch but think fuel filter may solve the issue as we dumped excess fuel into mason jar and saw some sediment.

While we are in maintenance mode are there any other popular issues that will cause this issue???

Thanks for any and all comments!