Gas Pressure Washer: Why is the spray from my pressure washer weak?

The check valves are spring-actuated pump valves that allow water to flow in one direction from the pump inlet to the pump outlet. If the check valves are worn out or defective, the pressure washer won't spray. Inspect the pump check valves and replace them if worn or defective.

The pump creates the water pressure when the engine is running. If the pump isn't developing any water pressure, replace the pump assembly.

The unloader valve reduces water pressure within the pressure washer pump when the pump runs but the spray wand isn't used, by recirculating water to the pump inlet. If the valve sticks in the closed position, the thermal relief valve frequently discharges hot water onto the ground because the unloader valve can't open to allow recirculation. If the pressure washer doesn't develop adequate outlet pressure, the unloader valve could be stuck open. Replace the unloader valve if it sticks in either the closed or open position.

If the water pressure hose leaks at the fittings, check each fitting for proper tightness. If you can't tighten the fittings, replace the pressure washer hose. Also replace the hose if it is split or damaged.