Karcher is the only brand that is able to do this. We sell a kit model 2.642-743.0 that makes the Karcher Electric Pressure Washer able to pull from a standing water source. If this is the kit you bought, I would like to give you a couple tricks to get it going.
Completely submerge the hose until the air is all out and it stops bubbling. Turn on the unit so that the pump starts working. Connect the hose until the pump stops humming then place the hose in the bucket so that is continues to have the positive draw.
For brand new units this will not happen instantly, I do recall waiting several minutes for this to take. (It can seem like forever) Hold the trigger gun and squeeze the gun to allow water to flow through the unit. After you have a positive draw the unit works just like it does when it is connected to a hose.
Karcher Suction Hose