Filling with fresh motor oil
Put the drain plug back on and do not over tighten. With both fill caps open, use a funnel to fill the motor with 10W-30 motor oil. Pour oil through the fill hole and continue until oil starts to come out of the second hole.

Use a funnel with a flexible tip to fill the motor with 10W-30 motor oil

Continue adding slowly till oil exits the motor through the fill hole on the opposite side of the motor.
How often should you replace the air filter on a pressure washer?