You may need to lower the motor 1/4 inch or so, see if that helps. I never run my '06 225ho less than 15# at WOT.

Interesting (not really), again another big block Etech that has the mid-section connection bolts loosen. It is important for owners to check these six bolts to ensure they are tight or not broken as sever engine damage can result. This situation happened to my motor too, and was not covered under the extended warranty.

Someone will chim in soon that may has a better opions than mine.
Mark