Three weeks ago I bought my first ‘real’ pressure washer. I had a small electrical one, but those are only suited to small jobs. This new one is so much better.
In case you aren’t familiar, a pressure washer connects to your garden hose and using an internal pump forces that normally low-pressure water flow through a nozzle, magnifying the water pressure.
A quick note: NEVER spray anyone with a pressure washer (and don’t spray yourself, either). If you had one of the higher-speed nozzles attached and forgot, you could cause serious injury. Pressure washers can peel skin right off a limb, and destroy delicate parts like eyes. No joke. Don’t let children use it, ever.
Using a pressure washer is easy, and there is no difference between an electrical and petrol one… attach garden hose, turn on water, turn on pressure washer, spray. Make sure you have a nozzle attached to the end of the pressure washer’s ‘gun’.
When buying, make sure your choice ranges between 1300 and 2600 psi of water pressure (mine is a 2200 psi pressure washer, and is more than powerful enough for practically any job), flows at 1 to 4 gallons per minute, and (of course) uses petrol. Also ensure that all the fittings are brass. Plastic fittings won’t last, and can result is dangerous breakages at inopportune times 
One final point, this time about pressure washer repair: don’t. Seriously. My motto is, if something could blow up or break apart at high speed if it isn’t properly fixed, don’t get it fixed. Replace it. A pressure washer pump itself may be easy for a shop to replace, and maybe your repair guy has the right signs and certifications (“we use only Karcher pressure washer parts, or Honda, whatever”) , but if the fittings and fastenings aren’t affixed just so, you’ll have parts flying around at bullet-speed. A good unit with the specs listed above should only cost a couple hundred, maybe 3. It will last for a few years, so use it right away and use it everywhere around your house, including pressure cleaning the outside walls of the house itself. But once it fails, replace it. Your face, your house windows, your neighbour’s kid.. none are worth risking a repair on.
