Outdoor Power Equipment (Lawn Mowers, Snow Blowers, Chain Saws and more) Discussions

I inherited my late father's Generac Pressure washer model 1460 and I'd like to change oil and do a little maintenance on the thing.

I've found the owner's manual online here: http://www.generac-portables.com/data/pdf_files/pw/1460_0en2w.pdf

But it doesn't give any specifics on the engine (in fact, the part number on the engine is "NSP", which I assume means "No Specific Part"). I know its a Honda 5.0, horizontal shaft, probably a consumer engine, but I don't know about the oil capacity, or anything else about it. Any ideas on this? Thanks for any help.