I don't have a 5 HP go-kart.
You can't go fast in Mario kart.
Probably faster than a 150cc kart
it will run 55-60mphbecause I have one and I got it up to 60mph.
This question cannot be answered with this information. There are too many variables like gear ratios, weight of the vehicle, etc. 5hp push lawn mower = 0mph. 5hp go gart = what, maybe 30mph 5hp engine in my car = not very fast!
Depending on what type of engine it is will tell you how fast it goes.