Don't go throwing away your pressure washer just because of a blown pump.
If the engine is still running strong, a replacement pump can be a much cheaper alternative.
Most entry-level pressure washers are equipped with wobble pumps, which are not replaceable.
However, better quality gas and high-end electric units have axial cam or triplex plunger pumps, which can be replaced.
Do Your Research
First, you'll need to make sure the replacement pump you're buying will be compatible with your current machine.
You'll need to know if the existing pressure washer pump is axial or triplex. Next, determine the shaft diameter-size and determine if it's solid or hollow.
Look at how the flange on your current pump attaches to the motor and measure the bolt pattern. Also, note how the pump sits in relation to the engine. Determine if your existing engine is horizontal or vertically shafted - meaning, does your pump mount next to the engine (horizontal) or underneath (vertical)?
You'll have to match your old pump's pressure rating (PSI) and gallons per minute (GPM) with those of an available replacement. Remember, more is not always better - getting a new pump that puts out a lot more PSI can either bog down the engine, or be too powerful for your hose's burst rating.
Check out the installation drawings or owner's manuals of replacement pumps that are similar to your current pump and compare the measurements to make sure your new pump will fit properly. Typically all major engine manufacturers produce the mounting flanges with the same measurements and specs.
However, it's highly suggested to double-check your measurements before you order; there is a 25% restocking fee on returned pumps.