ZX176C at anything over 70 is a freaking HANDFUL! Driving it is a constant "chopping wood" motion with the steering wheel and it takes quite a few attempts (lots of seat time) to figure it out.
During acceleration, mine would go from a little wiggle to severely diving off side to side in a second. I'd have to shut it down and start again. Over and Over until I finally figured out a timing pattern.
And even then, it's always going to walk.
You just have to time it to where you keep it bouncing on the starboard side.... and the port side never really hits the water.