I have a similar model with its manual. Like some lawn mowers, you just tip it over and pour the oil out the top. I didn't check the manual today, but as I recall, they suggest you pour so the air filter is up and out of the way.

Actually, CH is very helpful on the phone. Is this new? Used? Does it even have oil in it?!!

Thanks for the reply.

I hit it off craigslist. Where I'm a bit confused is which plug to pull, the big black plastic one or the small golden metal one below it?

No, no. The bottom stuff is the water pump. It has nothing to do with oil. I can't seem to find my manual although I was just using it last month. However, I went to CHpower.com and found (under service for power washer section) a manual for similar washers. However, it didn't include the Briggs and Stratton engine. I believe you could find the exact manual for your engine at their site. I had been looking so I could suggest the appropriate oil although it likely doesn't really matter that much.

The thing is, your machine looks very clean and perhaps unused. It may not even have oil in it. You certainly shouldn't try to run it until you find out and either add oil or remove and add oil. To remove, you hand unscrew the big black oil filler cap on the top left of the engine as shown in your first pic.; tip it over; pour it out. Yes, that seems odd, but that's the way some engines need to be emptied because (in this case) the pump is probably in the way of any regular drain port. But since it appears lightly used, you really shouldn't need to change oil.

Oh it's used just must be the lighting. The pump oil is what I'm inquiring about though. I just don't know which plug to pull (larger black plastic or smaller golden metal) to drain and don't want to mess anything up by opening the wrong one.

A Manuel should come in handy
to save some time, errors and possible damage.

1. Hopeful the engine’s oil
drain plug is extended out if the pump is blocking it. There are simple suction pumps for sucking oil
out if tipping is needed and not safe. A
drain in the bottom is the best for removing settled Etc in the oil...

2. Changing the oil in the
   pressure cleaning section could be as simple as the engine once the plugs and
   levels are identified.

3. I hate to admit that I started a new 1 HP
   Electric Campbell Hausfeld Air Compressor in 1972 without checking the oil. In
   seconds I turned it off after noticing the RED TAG. It was a returned unit (reduced in price) but
   that was not saying it had been used and oil was added. It had not been added. I needed it then on a job was the
   problem. I added oil, used it that day,
   checked the crank that night (and no signs of damage) and it still runs good today.

Yep, no worries about the motor. I actually repair small engines/equipment as a source of side cash I just have some weird apprehension about power washer pumps. Primarily because I have never messed with them and secondly because I can't find jack on my unit.

Fantastic. Thank you!

FYI re your pump: (my pump is slightly different but) it appears that the black hex drive cap (or whatever) that you showed in your second pic. is where the Unloader Valve resides. It is a little piston/seal thingie with a spring. I guess it is the business area of the pump (I don't really understand it). It should be easy for you to remove and clean/re-grease. (there may be a little brass set screw that you DO NOT, Should Not remove). I got mine out once, but now it is cruded up and things at the other end that originally could be internally unscrewed and removed so the unloader could be driven out from the back side is so discintegrated that it is now impossible to remove. There is a pump (suck) in a little vinegar, wait over night, pump in some salad oil, wait, rinse method that kind of works. I suggest that while your pump is clean that you pull the unloader out now rather than using the sad vinegar method. I think you should be able to find the cleaning method at chpower, but if not, they will link you to it via the phone.

I emailed them about a manual last night.

Thanks again!

Well would ya look at that???