Although the label said to mix the solvent 20:1 to degrease engine parts, I mixed it 10:1. Ten gallons of water (more or less) to one gallon of solvent concentrate.
Pump ran, pumped nothing. WTF.
...I had to remove the pump housing, disassemble the thing, and reassemble it; then it worked fine. In whatever Chinese factory spawned this thing, someone just slapped the pump into the housing and called it good; but it was not good. I put it together correctly and it worked as it should.
Considering what a similar parts washer costs from, say, Menard's, I'm not all that unhappy. For about ten minutes' worth of fiddling I saved $20 on the purchase price of the thing.
The real problem I have now is the solvent. You see, the solvent smells like window cleaner. When I mixed it with the water, it turned milky. It does not dissolve grease as a proper surfactant would; it seems to wash it away, and the oil floats on the surface of the solvent. Then it forms a ring around the tub.
Mind you, I stuck the spare Escort power steering pump in there; it is considerably cleaner than it was, but it's not what I would call properly cleaned.
Still, I put the pistons in and got them nice and clean (with the help of a brush with nylon bristles) and we'll see how it does with other parts later on. I'm not particularly worried about it.
At least I was able to use the thing.