Karche KB4040 Start problem

[bloggs15]

I have a KB4040 pressure washer that won't start properly the motor just hums but won't spin
I stripped it down and cannot find any obvious problems , the filters are clear etc, and I have checked the switch which seems to be ok, I have found that if I manually turn the motor say half a turn then it will start and spin up OK - but when it stops it won't start again until I move it manually again. Is this a problem with the start capacitor ? anyone got any other ideas ?

 

[TicklyT]

In a cap. start or cap. run motor, It could be the capacitor or one of the field windings.

Between them, the capacitor and second field winding generate a field out of phase with the supply current to kick the armature into rotary motion instead of just oscillating in an alternating field.

In a universal motor, it could be a brush jammed in it's holder, not making contact with all the commutator segments.