T, a jet has no torque effect, so, it shouldnt be doing that..did you replace the thin VERY flexible wire going from your servo too the nozzle? all that gotta be no slop at the servo and nozzle arm, and no flex.
Even with the jet slightly crooked in the boat, its the NOZZLE that determines direction..
As for the hoppin, of you noticed, I made some stainless trim tabs for mine to take that out..boat looks GREAT..
in about hour, I will be posting a short vid on the red one I finally finished for a friend..