On this page, you’ll find information on troubleshooting Simpson pressure washers. To begin with, you need to choose the table that was made up for your model of pressure washer (for instance, MS60799, Water Blaster, etc.). Now, try the suggested solutions to resolve the issue.
| OPERATIONAL ISSUE | POSSIBLE CAUSE | SOLUTION |
|---|---|---|
| Engine will not start | No fuel | Add fresh fuel |
| Pressure builds up after two pulls on the recoil starter or after initial use | Squeeze gun trigger to relieve pressure | |
| Choke lever in the “No Choke” position | Move choke to the “Choke” position | |
| Spark plug wire not attached | Attach spark plug wire | |
| Engine switch in OFF position. | Place engine switch in ON position. | |
| Choke lever in the “Choke” position on a “hot” engine or an engine that has been exposed to thermal heat for a long period of time. | Move choke to the “No Choke” position. | |
| No or low pressure (initial use) | Spray wand not in high pressure | |
| Low water supply | Water supply must be at least 5 gpm 20 PSI | |
| Leak at high pressure hose fitting | Repair leak. Apply sealant tape if necessary | |
| Nozzle obstructed | ||
| Water filter screen clogged | Remove and clean filter. | |
| Air in hose | Turn off the engine, then the water source. Disconnect the water source from the pump inlet and turn the water source on to remove all air from the hose. When there is a steady stream of water present, turn water source off. Re-connect water source to pump inlet and turn on water source. Squeeze trigger to remove remaining air | |
| No or low pressure (initial use) | Choke in the “Choke” position | Move choke to the “No Choke”position |
| High pressure hose is too long | Use high pressure hose under 100 feet (30 m) | |
| Will not draw chemicals | Spray wand not in low pressure | |
| Chemical filter clogged | Clean filter | |
| Chemical screen not in cleaning solution | Make sure end of detergent siphon hose is fully submerged into cleaning solution | |
| Chemical too thick | Dilute chemical. Chemical should be the same consistency as water | |
| Pressure hose is too long | Lengthen water supply hose instead of high pressure hose | |
| Chemical build up in chemical injector | Please contact our customer service department | |
| No or low pressure (after period of normal use) | Worn seal or packing | |
| Worn or obstructed valves | ||
| Worn unloader piston | ||
| Water leaking at gun/spray wand connection | Worn or tom o-ring | Check and replace |
| Loose hose connection | Tighten | |
| Water leaking at pump | Loose connections | Tighten |
| Piston packings worn | Please contact our customer service department | |
| Worn or tom o-ring | ||
| Pump head or tubes damaged from freezing | ||
| Pump pulsates | Nozzle obstructed |
| PROBLEM | PROBABLE CAUSE | SOLUTION |
|---|---|---|
| No Pressure. | Broken Belts. | Replace Belts. |
| A.P.R. system binding. | Remove A.P.R., flush UV with water. Clean A.P.R. parts and replace. | |
| Worn Piston U-Cup. Debris In Valves of Pump. | Rebuild Unloader Valve (Service Center). Remove Valves and clean. Flush Manifold. Install Inlet Water Filter. | |
| Not Unloading. | Leak in Gunvalve or Hose. | Repair gun leak . Replace leaking or broken hoses. |
| Debris or wear in Check Valve. Check O-Ring. | Remove Check Valve parts and dean. Reface with emery cloth, or replace check valve. | |
| Damaged Piston U-Cup. | Rebuild Unloader Valve (Service Center). | |
| Low Pressure. | Worn or Incorrect Nozzle Size. Improper belt tension. Improper engine R.P.M. Inadequate water supply. | Replace Nozzle with proper size. |
| Tighten or replace belts. | ||
| Adjust R.P.M. with Tachometer. | ||
| Check supply. Clean or replace Inlet Water Filter. | ||
| Water in Pump Oil. | Worn Plunger Seals. | Replace seals with Plunger Seal Repair Kit. |
| Worn or damaged Plungers. | Check for wear or cracks. Replace. | |
| Sand or dirt entering system. Running Pump dry. | Check or install Inlet Water Filter. Do not use well water. | |
| Check water supply and Inlet Water Filter. | ||
| Pump Oil Leak. | Oil level too high. | |
| Wrong oil type. | ||
| Water in oil. | Damaged Plunger Seals or Plungers. Adjust engine R.P.M. with Tachometer. Move to level surface. | |
| Engine R.P.M. too high. Operating on unlevel surface. Tire pressure too low or flat. | Inflate tire(s) or repair leak(s). | |
| Recoil Hard to Pull. | Broken A.P.R. Spring. | Replace A.P.R. Spring. |
| Note: A.P.R. Spring should be replaced every year or after every 500 hours. |
| Problem | Solution |
|---|---|
| Is the engine running at full speed? | Move the throttle control to the FAST. |
| Is the low pressure nozzle connected to the wand? | Switch to a high pressure nozzle |
| Is the water inlet or filter screen blocked, clogged or damaged? | Disconnect the garden hose from the water inlet; clean the water inlet and filter screen. If screen is damaged, remove damaged screen, insert new screen |
| Is the high-pressure hose leaking? | Check the O-rings. If damaged, remove old O-ring with a small flathead screwdriver, and replace with new one |
| Is the spray gun leaking? | Replace the pressure washer spray gun with a new one |
| Could the nozzle orifice be obstructed? | Shut off the engine; purge air from the pump; remove the orifice from the adjustable nozzle or remove the spray tip from the nozzle extension; clean the orifice or spray tip using the wire tool from the maintenance kit. |
| Is the supply water temperature over 100° F? | Provide a cooler water supply |
| Is the supply water pressure and flow rate adequate? | Test the supply water using a pressure/flow-rate gauge. If the supply water does not produce a minimum of 20 PSI and 4 GPM (25 PSI and 7 GPM for POWERflow+ models), look for an alternative source that can provide adequate pressure and flow |
| Is the pump oil level low? | Add oil to the pressure washer pump |
| Is the pump faulty? | With the high pressure hose removed from the pump, attach the garden hose and turn on water. Water will flow through the pump, now turn on the engine; the water flow should increase in pressure and length from where it exits the pump. If this does not happen there is an internal pump issue. If this does happen then there is likely a clog in one of the attachments; high pressure hose, gun, wand, or nozzle |
| Problem | Solution |
|---|---|
| My pressure washer will not start | After ONLY 30 days of downtime the fuel in your gas pressure washer may turn stale. It is important to always stabilize your fuel to prevent moisture from leaching into your fuel. Some people recommend that you drain your fuel and this is a good method, but still leaves your pressure washer susceptible to moisture contamination in your tank and carburetor. |
| LEAVE your tank full and use Ethanol Shield to prevent moisture contamination | |
| My pressure washer’s pump seems to be damaged after only one season of use | If you did not winterize your SIMPSON it could be that some residual moisture in your pump expanded in cooler months, causing tiny cracks in your pump. Winterizing will prevent any residual moisture from freezing, expanding and potentially cracking valves and seals inside your pump |
| My pressure washer only gives me low-pressure | Your SIMPSON may be operating in low-pressure due to an incorrectly sized nozzle or a nozzle that has worn out. |
| Always replace any worn or broken nozzles as they can potentially be a safety hazard. | |
| ALWAYS use accessories that are within your pressure washer’s PSI range. You could be losing pressure because your accessory is meant for a higher/lower PSI range than your machine and can cause damage to your accessory. | |
| Be sure to check if the water is fully turned on and there is enough water flowing through the pump. Check your pumps filter on the inlet to make sure there is no debris blocking the water flow. A hose that is vertical or too long may delay water pressure from arriving fast enough | |
| My pressure washer is running very roughly | If you have a hot-water and cold-water outdoor faucet always make sure to use cold water for best results. |
| If you don’t have a hot water faucet, water that has been trapped in a hose with sun directly on it may be enough to cause your pressure washer to run a bit rough. If this happens turn off your machine, disconnect hose, and let water run until it is cold | |
| You may also check your air filter inside of your engine to be sure that it is clear of any debris. | |
| If all looks good and you aren’t using hot water, then you may have mechanical damage within your pump and will need to call SIMPSON’s technical support line | |
| My pressure washer pump is leaking water | If your pump is leaking water it could be caused by the following: |
| If you let your pressure washer run for longer than 2 minutes at a time it will enter into bypass mode. This means that the water inside of the pump is continually flowing and heating up. When your pump is too hot it will cause damage and can potentially crack. To prevent the pump from over-heating, your SIMPSON is equipped with a thermal relief valve (safety feature only) that will release hot water when the pump becomes too hot. | |
| Be sure to turn off your machine if you take breaks longer than 2-3 minutes. | |
| If your pressure washer is leaking at the gun, wand, or nozzle it could be that your accessories are not secured tightly enough. Turn off your machine and ensure everything is tightened properly | |
| My Pressure washer just shut off during use | SIMPSON pressure washers are designed to ensure you do not damage the engine or any of the mechanical components. Generally, the reason your SIMPSON pressure washer just shut off is because it has run out of gas or oil. |
| ALWAYS check the oil and gas level of your pressure washer every time you plan to turn it on. | |
| A person checking the oil and gas level of a SIMPSON® pressure washer | |
| I am unable to disconnect my high pressure hose and garden hose from the pump | Once your pressure washer and water source are turned OFF and you are unable to disconnect your hoses from the pump and gun it is generally due to pressure that is still inside of the machine. To relieve this pressure simply squeeze the trigger to release any water and then try disconnecting hoses again. |
| A women disconnecting a SIMPSON® pressure washer in a yard by squeezing the gun trigger to release water | |
| My pressure washer will not draw soap | Always be sure that your low-pressure soap nozzle is inserted in your wand. If you have any high pressure nozzles attached to the wand your pressure washer will not draw in soap |
| Am I using the correct chemical for my pressure washer? | Always use a pressure washer safe soap for cleaning. NEVER use bleach or other caustic chemicals, as this will damage your pump and cause it to fail. |
| There are various soaps that are specific for your cleaning job. When pressure washing siding be sure to check the label on your soap to see if it is safe. Always test out a small area of your surface before applying soap to full surface area to prevent any damage |