Since you don't mention either the model of the pressure washer or the model numbers of the Honda engine it's impossible to tell what machine you have.

If you've go a professional model GX Honda (OHV), rebuilding the carburetor might make more economic sense, as the Keihin carburetors are very expensive. On the other hand, the carburetors on the GC series (OHC) are so much less expensive, I wouldn't recommend fooling with the carb. Simply buy a new one and replace, rather than rebuild.