Bob if there is any way to post an image of your carburetor, some of us might be able to help with identifying or at least we might see some clues. For what it may or may not be worth, I have used an electric fuel pump since 1996 and I've learned about 2.5psi to 3psi pressure is ideal for the 235.
One thing which could be important here: unless I missed it I'm not certain which year of 235 you have. There were several versions of the YF made for 235s. They all recognized differences in design for the engine. And there were numerous YF models made for many other makes of vehicles, too. We're happy to help.
