I had replaced the cartridge filter thinking that was the problem
but obviously it wasn't. That's what got me thinking the pump is the
problem. Did JD place the pump in the tank? I traced the line back to
the tank and no pump. The tank is hidden under the seat and not
clearly visible.

From what I can see on the drawing in the parts book; it is a
mechanical pump bolted to the engine. The pump has an arm that looks
just like a miniature version of the pumps that were on car and truck
engines before fuel injection.