Skeeter ZX202c top speed / handling issue?

Hi guys, I've got a '97 Skeeter ZX202c w/ Yamaha 200 pro-v turning a Yamaha 25m prop. previously had a 24 turbo lightning prop. has a 12" hydrodynamics jack plate on it (I believe about 2.75 below pad but haven't measured - previous owner told me it was set up for top speed already)

With both props I got a top speed of 64-65.5 GPS in ideal conditions w/ half tank of gas and very light tackle. Running at 5900 RPM's. I'm not throwing much of a rooster tail, the spray is hardly higher than the cowling when trimmed up.

Whenever I get above 5400 RPM or above 60 mph, the boat is really hard to turn. I have to CRANK the wheel to get it to turn (though it doesn't skip or feel squirrely) Below ~5400 / 55mph, I can easily turn with one hand. The boat has 1 year old hydraulic steering so I don't think that's the issue at all.

I'm going to lower the motor about .5 next time I have it out to see if that helps, but was wondering if anyone else has experience with this model that could comment on the set-up, or if anyone knows what could be causing this handling issue.

Sounds about the right speed. If its hard to turn LEFT and easy to turn right you have a torque problem. If you have a torque tab on your lower unit and its straight you can turn it so its countering the motor torque. If you don't have one you can add one to the skeg.

Sounds like jack plate too high. Lower in 1/2 inch increments until problem fixed.