I don't know what the type of motor is in the 8000NC but, assuming it's an ac motor with a start/run capacitor, capacitors used in start/run synchronous induction (ac) motor applications have to have characteristics suited to being continuously connected to the motor.
Depending upon how the starter winding is connected, in relation to the motor winding, then the capacitor is either passing current in series into the starter winding, and depending upon the configuration of the motor windings, may also have the peak supply voltage across it continuously.
I guess selection of a capacitor depends heavily upon knowledge and understanding of the characteristics of the motor if a reliable alternative replacement capacitor is to be selected.
The size of the task is irrelevant - what matters is that the individual selecting the component has the skill and the information available to do it and ensure it's reliable, i.e. the design's been validated or checked by the manufacturer.
