Simpson Pressure Washer Manuals

Gas Pressure Washer Engine Will Not Start

• No fuel: Fill the tank with fresh gasoline and confirm the fuel valve is open if your model includes one.
• Old fuel: Drain stale fuel and refill with fresh fuel after long storage.
• Choke setting wrong: Use the correct cold-start or warm-start procedure shown in the model-specific manual.
• Low oil shutdown active: Check the engine oil level and add the recommended oil if needed.
• Spark plug issue: Inspect the spark plug, plug boot, air filter, engine switch, and stop control before further troubleshooting.

Electric Pressure Washer Will Not Turn On

• Power cord loose: Plug the pressure washer directly into a working grounded outlet.
• GFCI tripped: Press the reset button on the GFCI plug or outdoor outlet and check for moisture around the connection.
• Outlet has no power: Test the outlet with another device and check the breaker.
• Trigger not squeezed: Some electric pressure washers run only when the spray gun trigger is pressed.
• Thermal protection active: Turn off the washer, allow the motor to cool, and check for water-flow restriction before restarting.

Engine or Motor Runs but No Water Comes Out

• Water supply off: Open the faucet fully and confirm water flows freely through the garden hose.
• Air trapped in pump: With the unit off, squeeze the trigger until a steady stream of water flows from the spray gun.
• Inlet screen clogged: Remove and clean the water inlet filter before reconnecting the garden hose.
• Nozzle blocked: Remove the nozzle and clean the orifice with a nozzle cleaning tool or small cleaning pin.
• Hose kinked: Straighten the garden hose and high-pressure hose to restore proper water flow.

Low Pressure or Weak Spray

• Wrong nozzle selected: Use the correct spray tip for the surface. A wide-angle nozzle produces less cleaning force than a narrow-angle nozzle.
• Water supply too weak: Make sure the faucet is fully open and the supply hose is not too narrow, long, kinked, or restricted.
• Nozzle worn or damaged: Replace the nozzle if the spray pattern is wide, uneven, or weak.
• Inlet filter dirty: Clean the inlet screen to prevent reduced pump flow.
• Unloader or pressure control issue: Adjust only as described in the manual. Incorrect adjustment can reduce pressure or damage the pump.

Pressure Pulses, Surges or Drops

• Air leak at inlet: Check the garden hose connection, inlet adapter, gasket, coupler, and filter screen.
• Water supply unstable: Confirm steady flow from the faucet and avoid using a collapsing or damaged hose.
• Nozzle partly clogged: Clean the nozzle and flush the spray wand before reinstalling it.
• Unloader valve sticking: A sticking unloader can cause surging, bypass problems, or unstable pressure.
• Pump valve problem: If pressure remains uneven after cleaning the inlet and nozzle, pump valves or seals may need inspection.

Pressure Washer Leaks Water

• Garden hose connection loose: Tighten the inlet connection by hand and confirm the washer gasket is installed.
• High-pressure hose loose: Reconnect the hose to the pump outlet and spray gun until fully seated.
• O-ring damaged: Inspect quick-connect fittings, spray wand ends, hose couplers, and nozzle sockets for worn O-rings.
• Cracked fitting: Replace damaged adapters, couplers, spray gun parts, pump fittings, or hose ends.
• Pump seal leak: Stop using the washer if water leaks heavily from the pump body, oil area, or between the pump and engine.

Detergent Will Not Dispense

• Wrong nozzle used: Many Simpson pressure washers draw detergent only with the black low-pressure soap nozzle.
• Detergent tank empty: Fill the detergent tank or connect the soap siphon hose correctly.
• Soap tube blocked: Check the detergent hose, filter, tank outlet, and siphon tube for dried soap or debris.
• Detergent too thick: Dilute the cleaner according to the detergent instructions.
• High-pressure mode selected: Switch to low-pressure soap mode before expecting detergent flow.

Spray Gun, Wand and Nozzle Problems

• Nozzle will not lock: Pull back the quick-connect collar, insert the nozzle fully, then release the collar until it clicks.
• Nozzle pops out: Stop using the washer and inspect the quick-connect coupler, retaining collar, and nozzle groove.
• Trigger stuck: Engage and release the trigger lock, rinse the trigger area, and inspect for dirt or damage.
• Spray pattern uneven: Clean the nozzle and replace it if the spray remains distorted.
• Wand leaks: Check the O-ring, threaded connection, quick-connect fitting, and gun-to-wand seal.

High-Pressure Hose Problems

• Hose difficult to connect: Turn off the washer, shut off water, and squeeze the trigger to release pressure before reconnecting.
• Hose kinks: Lay the hose out straight before starting and avoid tight loops while cleaning.
• Hose leaks under pressure: Replace the hose if it is cut, blistered, cracked, flattened, or leaking.
• Hose stuck on fitting: Release pressure first, then disconnect carefully without forcing or twisting the fitting.
• Wrong hose rating: Use a hose rated for the washer's maximum PSI and compatible fitting type.

Surface Cleaner Problems

• Surface cleaner not spinning: Check for clogged spray jets, low water pressure, or debris under the rotating bar.
• Uneven cleaning lines: Move at a steady pace and overlap passes slightly for consistent cleaning.
• Heavy vibration: Stop and inspect the rotating spray bar, nozzles, bearings, housing, and skirt for debris or damage.
• Circular marks appear: Keep the cleaner moving and avoid excessive pressure on delicate or uneven surfaces.
• Water splashes excessively: Check the skirt, nozzle condition, and surface cleaner compatibility with the pressure washer model.

Pump Problems

• Pump will not prime: Connect water, open the faucet, and squeeze the trigger until all air is purged before starting the engine or motor.
• Pump gets hot: Do not leave a gas pressure washer running for long periods without squeezing the trigger.
• Pump oil issue: For serviceable pumps, check pump oil only if the model manual specifies pump oil maintenance.
• Pump frozen: Stop use immediately if the washer was stored in freezing temperatures with water inside.
• Pump noisy: Check water supply flow, inlet filter, air leaks, and nozzle blockage before assuming internal pump damage.

Engine Runs Rough or Stalls

• Old gasoline: Replace stale fuel and use fresh fuel for reliable starting and stable running.
• Dirty air filter: Clean or replace the air filter according to the engine manual.
• Carburetor dirty: Fuel varnish or debris in the carburetor can cause surging, hunting, or stalling.
• Nozzle clogged: A blocked nozzle can overload the pump and affect engine performance.
• Low oil level: Check the oil level if the engine shuts down unexpectedly.

Oil Leak or Milky Pump Oil

• Pump seal problem: Water entering the pump oil can make it appear milky and may require seal service.
• Oil overfilled: If the pump is serviceable, verify the correct oil level according to the manual.
• Loose drain plug: Check pump oil drain and fill plugs where applicable.
• Cracked pump housing: Stop using the washer if the pump housing appears cracked or damaged.
• Engine oil leak: Inspect the engine oil fill cap, drain plug, crankcase area, and mounting surface.

Unit Stops During Operation

• Low fuel: Refill the fuel tank with fresh gasoline.
• Low oil shutdown: Check and correct engine oil level.
• Thermal shutdown: For electric models, let the motor cool and check nozzle, inlet filter, hose, and water supply restrictions.
• Water supply problem: Restricted inlet flow can cause pressure loss, overheating, or shutdown.
• Overload from clogged nozzle: Clean or replace the nozzle and flush the wand before restarting.

Winter Storage and Pump Protection

• Water left inside: Drain the pump, spray gun, wand, hose, and accessories after use.
• Freezing damage: Never store the pressure washer where water inside the pump can freeze.
• Detergent residue: Flush the detergent system with clean water before storage.
• Fuel storage: Drain or stabilize fuel according to the engine manual before long-term storage.
• Pump protector: Use pressure washer pump protector or antifreeze storage solution if recommended by the manual.

Routine Maintenance Tips

• Flush before use: Run water through the garden hose before connecting it to remove dirt, sand, and debris.
• Clean inlet filter: Inspect the inlet screen regularly and clean it whenever flow seems reduced.
• Inspect seals: Check O-rings, washers, adapters, quick-connect fittings, and hose ends before each use.
• Release pressure after use: Turn off the engine or motor, shut off water, and squeeze the trigger before disconnecting hoses.
• Store dry: Drain water, coil hoses loosely, store nozzles together, and keep the washer indoors in a dry location.

Safety note: Always wear eye protection and keep the high-pressure spray away from people, pets, electrical outlets, windows, vehicles, painted surfaces, and delicate materials. Never point the spray gun at yourself or others. Shut off the engine or unplug the unit, close the water supply, and release pressure before changing nozzles, connecting hoses, or performing maintenance.