Got a Dewalt 3800 PSI Pressure Washer with 4.0 GPM with a Honda GX 390 gas engine. Tipped it up to roll it out to my truck and got a big puddle of water with what looked like Pump oil in the puddle. Can you help???? It is less than a year old with 10-15 hours on it.....

Replace hose gasket

I found a small long spring disconnected from my throttle which made the engine run rough It is easy to reconnect and makes a big difference in engine performance. also, if there is a very dirty air filter-oil/dirt it will not start-replace filter.

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?

Non-detergent 20-30-weight goes into pump port, and is filled about half way.
Ordinary motor oil 10-W30 or 40 goes into engine port.

If you need further help, I’m available over the phone at https://www.6ya.com/expert/gene_9f0ef4df2f9897e7

Kleen- rite has a video on how to rebuild the cat 330 pump which is pretty similar to this pump very helpfull video

in the enginge you can use a standard 4 stoke engine oil.
in the pump you can use hydraulic oil

The numbers you have listed are for the engine, Honda doesn't actually make pressure washers but makes the engines. If you are looking for the manual on the pressure washer itself you are going to have to find some other numbers that should be listed on the frame of the machine.

inlet .006 exhaust .008

There are no manuals for Dewalt at either of those sites.

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.