Building an alternate nozzle for a Karcher K5.540 Power Washer

It seems like a rather odd thing to do, but in order to support a recent project, I needed to find a way to replace the gianourmous spray gun attachment which ships with the Karcher K5.540 with something a bit smaller.  The resulting sprayer nozzle looks like this when assembled:

The Karcher units are a little tricky as they use a proprietary fitting on their hoses.  Luckily, RJ Bowers carries a part (black piece above) which connects the high pressure hose via a quick connecter and terminates in a common M22 thread.

The four magic pieces used to assemble the sprayer gun replacement are as follows:

• RJ Bowers: Karcher 4.470-041.0 (4470-0410)
• General Pump M22 Male to 1/4" NPT Male Adapter (D10021)
• Brass Sleeve-Lock Socket, 1/4" NPTF Female, 1/4" Coupling (6537K73)
• Briggs & Stratton 6193 Quick Connect Spray Tips (6193)

The B&S quick connect spray tips come with a variety of angles:

• Black - low pressure tip
• White - 40 degree
• Green - 25 degree
• Yellow - 15 degree (seen in the above picture)
• Red - 0 degree

The red tip is fairly useless unless you are planning to write your name in concrete.  The next most powerful is the yellow tip at 15 degrees.  The resulting spray is not quite as intense as from the original spray head (perhaps the nozzle output hole is too large), but is still respectable and has a much smaller profile.  In short, its perfect for the prototype system I'm working on.

I initially had some concerns about back pressure from the new head, but based on the results, I do not think it will be a problem.