Definitely shouldn't hop to a point where it leaves the water.

A ProComp STV doesn't need a jack plate with a 20" motor, and definitely doesn't need a hydraulic plate. Only reason (typically) to run a plate on a ProComp is if you're running a 15" mid.

Propshaft should be at least an 1" above the pad. What type of gearcase? Stock w/nose cone? CLE? Sportmaster? Best running case on an STV is a Sportmaster. What prop? Cleaver? ET? Round ear? Can't go wrong with a good Mercury cleaver on these boats too. For a 260/Pro Comp, a good all around prop with be a nice Merc Cleaver 14.5" x 30".

Steering needs to be tight! Is is hydraulic or cable? If it's hydraulic, most likely its a Seastar ram. Find the directions on how to bleed and get the play out of it.

These boats do not need positive trim at speed. Neutral to slightly negative. They have natural lift in the hull. Depending on the healthiness of that 260, the boat should run well over 100, and if it's a good one, into the teens. Will also depend on how heavy a layup the boat is too.

We had a ProComp years ago and it had the ModVP bottom, was fairly light and would run high teens with ease. However, we did have an issue early on similar to what you're going through and we found the motor had been mounted slightly crooked from when it was new.

Any pics of the boat?

14 year old thread..........

and he still hasn't figured out how to drive it......