20 Most Recent Dewalt 3800 PSI Pressure Washer Questions & Answers

John Deere will replace the cap for free; they acknowledge the vendor who supplied Briggs & Stratton gas caps provided faulty caps. Call 1-888-228-3068 then 1 (English), 2, 1 and a technician will ask you for model number and Serial Number (which they need to replace the cap). Don't drill a hole in your cap: debris will find a way into the gas tank and end up possibly fouling the engine. Bob from NJ

Had a similar issue with my dewalt 4200 pw. Unit starting shutting off after spraying for about 5 min. Then difficult to restart, but would start again eventually only to shut down a few min later. Had new engine oil, new pump oil, good gas. I changed the spark plug and unit runs great again!

Remove spark plug and clean with dry cloth and then put a teaspoon of gas in the hole where spark plug was installed. Next reinstall spark plug and try starting. It should start.

Are you saying that it WONT start or that you cannot pull the rope to get it to start?

I worked at a tool rental center while attending college and learned many tips and tricks about Dewalt and other brand pressure sprayers. Your machine probably has a 13 hp honda and has max pressure of about 3500 to 3700 psi. Most of the problems that customers had were engine related due to severe working conditions including totally wet engine /plug, wet air filter, and or other problems that were easy to remedy. We would set the pressure regulator to minimum pressure and explained to the customer how to increase the pressure as necessary but only after the engine was completely warmed-up to running temp to prevent engine stall. Your machine has a throttle lever between the tank and carb that should be set to max if you are going to set pressure at or neer max range. Most cleaning jobs do not need much pressure. Use lowest pressure to get the job done. Your engine developes around 13hp at about 3600rpm. If you want to maximize the life of you sprayer, then use your machine at about 70% of capacity or about 2000 to 2500 range that will allow you to run your engine slower increasing lifespan. Your sprayer is likely rated at 4 gallons per minute so make sure that the tip is that capacity. The tip has the size stamped which would show the fan degree and flow in gpm. The wrong tip, say a 3.5 gpm will strain the engine to point of stop because the smaller tip increases pressure. Most engine stall is due to high pressure setting on new machines. Lower pressure when warming-up machine and use max pressure rarely when necessary to max life. Please email for other information/questions or simple tests to determine faulty parts, good luck.

Possible wand jet blocked, remove and unblock jet. Check and top up oil level in the engine and pressure pump, Check if there is fuel and what is the fuel quality in the fuel tank. Is the engine spinning and does'nt start or is locked?

I have the exact same pressure washer and have had the same issues with it. The cure for me was to simply run the washer with the gas cap loose. For some reason the fuel gets vacuume locked and stops flowing into the carb. The fuller the tank is it seems the shorter the time is between the time it starts and the time it shuts off. Or you might find a way to vent the cap. Hope this helps.

You must have blown out the cones (thats how the water gets compressed inside of pump) in the water pump- You could try this though on the back of the washer right on top of the water pump is a black knob about the size of your hand that knob will adjust the pressure try turning it and see although I doubt that is the problem- A pressure washer is not like a compressor you HAVE to pull the trigger every minute NEVER let it just sit there running without pulling the trigger to release the pressure that Dewalt 3800 psi washer you have is a great machine in fact we own 4 of them and they are pretty powerful and easy to damage if left running alone. TY, Perry Tradesman

When you pull to start squeeze the water hose tigger until start.

You checked the output to measure 5 GPM? How are you feeding that unit? What are you using for detergent? Have you adjusted the bypass valve?

there is an adjust screw on the pump.most pressure are set for the high setting from the factory

Try to clean the spark plug and make sure it is gaped properly Best of luck!