As I said before, I've replaced dozens of them switches before due to being burnt out. When you ask the owners 'Were you using a heavy duty extension lead fully unwound, like you were told when I sold you the washer?' 99% of the time they go red & say they were using the lead they bought in B&Q for the lawnmower. 
Check what size your motor is & what the running amps are then set the new overload to 10% above that.
Check what size your motor is & what the running amps are then set the new overload to 10% above that.
