Here are some of the factors that will affect the top speed of a 9 horsepower go-kart:
* Weight: The heavier the go-kart, the slower it will accelerate and the lower its top speed will be.
* Terrain: Go-karts are most efficient on smooth, paved surfaces. They will lose speed when traveling over rough terrain or inclines.
* Drivetrain: The type of drivetrain (chain or belt) and the gear ratio will affect the top speed of the go-kart. A go-kart with a high-performance drivetrain and a high gear ratio will be able to reach higher speeds than a go-kart with a less powerful drivetrain and a lower gear ratio.
In general, a 9 horsepower go-kart will be able to reach speeds of between 20 and 40 miles per hour.