I have a champion red 1800w power washer. it seems to run ok without the hose attached but as soon the hose is attached and the water turned on it only makes a buzzing sound
there is a pressure relief/recirculation valve inside the pump which probably needs cleaning and a bit of lubrication. I did find an exploded diagram once for a similar washer but you'll have to go searching like I did, as I no longer have the link.
