Its the venerable carter P4070. being mounted above the tank, it requires constant flow to keep the pump primed. The fuel pressure gage is teed into the return line to the tank. I have a plug in the return line with a 1/16" hole through the center of the plug. This keeps the pump flowing about 5 gallons or so per hour
For really grungy de-greasing like that. I buy a paint can at the hardware store and fill it with kerosene. I'll soak the parts and then brush them under the surface of the liquid with a nylon or brass brush. Under the surface of the liquid keeps the globs of kerosene soaked grease from flinging all over the place. Diesel also works but smells a bit more. Of course mineral spirits and WD40 work well too, but the cheap bastard in me likes the 3 bucks a gallon for kerosene/diesel at the pump.