The problem with Honda helping with an "after-market" product that has a Honda General Purpose engine on it is this: Honda takes responsability for the engine only. The engine is the Honda Product, not the attatched accessory.
Many People, many people assume that because the "name-brand" product has a Honda engine on it, it is a Honda product.
I hear this ALL the time.
For help with your "troy-bilt" pressure washer is to go to troy-bilt and get the information on the "troy-bilt" portion of your equipment. If it is another company using the troy-bilt name, you need to contact that company for information.
For help with the engine, any Honda powered product dealer, I am sure would be more than happy to help you.
As far as problems with manufacturers using names, the most recent fiasco I personally experienced is a "Homelite" generator with a Honda engine on it.
This is not a homelite product. But it has a homelite name. It has a Honda engine on it. But it is NOT CARB COMPLIANT. It is distributed from an outfit in Arizona.
Honda has their own line of powered products.
Putting a Honda Accord engine in your Toyota does not make your Toyota a Honda Accord any more than putting a Honda General Purpose Engine on a Troy-bilt tiller make your Troy-bilt tiller a Honda Tiller.
Now that I have tried to explain the difference in Manufactureres, please tell me who really makes your pressure washer, or provide pictures and model information so I can attempt to get you some service information.