Q: Can a start capacitor be interchanged with a run capacitor?
 
            
                    
                         A: Yes and no. In unusual circumstances, a run capacitor could be used as a
 start capacitor, but the values available are much lower than the 
values usually available for dedicated start capacitors. The capacitance
 and voltage ratings would have to match the original start capacitor 
specification. A start capacitor can not ever be used as a run 
capacitor, because it could not handle current continuously (only a 
couple of seconds).