Another vote for the switch. The start capacitor is staying in circuit so the winding is overheating as is the cap.
I don't believe that motor has a centrifugal switch
^^^^thats a lot of water in a plastic case with 240v mains
Just take the damned thing apart and let's have done with it
It's your motor. If you fit the new capacitor and it fails again then there's the possibility that, this time, it could damage the winding to the point that the motor's scrap. Your call.
Why do you think that it has the switch when a number of other people seem fairly sure that it does not?