Is your motor functioning?
Do you have any data belonging to the scooter model? (If yes, you may be able to find the motor used, and access the datasheet).
There are TWO major powers that are of concern with motors. THE FIRST is the input electrical power. This power, also known as Pin (because it's the input power), is:
P = VI, where P is in Watts, if V is volts and I is in Amperes.
The OTHER power is the motor output MECHANICAL power (that is, the mechanical rotational power the motor exerts). This is:
P = T*w, where T is torque (in N.m (Newton-Meters)), and w is angular velocity (in radians/sec). P is then in Watts. If you're American, you may want to use RPM and H.P.
In this case, use an online converter, or look at what torque/rotational units you need to use.
The two powers are not the same. The MECHANICAL power will always be LESS than the input electrical power (due to the second law of thermodynamics), and the ratio of the two:
n = Pout/Pin, where the same units are used for P, and Pout is mechanical power.
n will change depending on the loading (how difficult it is to turn whatever's attached to it) and the voltage applied to the motor. But assume 24V, if there seems to be no other voltage control in your scooter.
If you do some simple experiments, find the speed-torque curve of your motor (assuming it still runs). Do this by finding the torque (applied load) that makes the motor stop moving. This is one data point. Next, find another data point between the load and the speed.
Since the relationship between the torque applied to the motor and the speed of the motor is ideally linear, you can use this characteristic to find the LINEAR relationship between the torque applied, and the speed of the motor. If you like, make a line of best fit.
Since the OUTPUT power of the motor is the torque times the rotational velocity. You can generate an output power parabola as well. From all this data, should definitely find a motor (given a motor's spec. sheet provides motor curve info) that matches your application. Just make sure the current of the new motor isn't too much higher.