This is something that has happened to me several times and although it
is simple and might be overlooked its worth a shot. Because the motor
was running while you powerwashed and ran afterward even if it was for a
hundred miles dont overlook the possibility of -- steam. The water will
vapor to steam INSIDE the dist cap and while running have no effect but
when you shutdown and let it cool it condenses and becomes water
droplets that simply short the cap and prevent the proper spark causing
it not to start. It may even start but not without effort and will run
poorly.
I would suggest a second look at the electricals and make quite sure
they are all dry. I normally leave the cap off after drying for several
hours to be sure that the cap and dist are dry. The same holds true of
the wires and their  connections in the cap aand coil.
Just my two cents worth