If you think about it, a gas-powered pressure washer is basically an engine and a pump.
Medium consumer gas pressure washers feature direct drive systems with axial cam pumps. The size of the engine, however, determines the strength (and price) of the pressure washer.
Basically, you’re buying cc's. The greater the cc's – the larger the engine – the more expensive the pressure washer.
What Can it Do?
With 3000 PSI, the more appropriate question may be, what can't it do? These pressure washers have the power to take on some of the toughest stains. They even have enough power to strip old paint.
All medium consumer gas units are cold water - meaning, your main limitations will be related to hot water cleaning. If you need to remove oil or grease stains, a cold water power washer probably won't cut it. To get these messes clean, you'll want to step up to a hot water unit.