Fuel Pump Question

Not my boat, a neigbor's. Not a CC but a Supra with an Indmar. He had his fuel pump replaced a week ago and was all happy because his boat ran a ton better than previously (He just bought it this spring) After a couple days it stopped working, kept popping fuses that he thought was fuel pump related. After some diagnostics, he discovered if he unplugged the elect connection to the item shown in the center of this photo, the boat ran fine. He asked me what it was, as the fuel pump he had replaced was a 6" x 1.5" cylinder bolted to the top of his fuel water separator/filter just down stream in the fuel line from this thing. I said I didnt know, but that I had heard you guys talk about two fuel pumps, low pressure and high pressure, but that I knew nothing more than that. I surmised that this device that allows the boat to run when unplugged might be either fuel pump, but I have no idea. So thats what I'm asking. Is this one of two fuel pumps and if so, why can the boat run fine with it unplugged. What does he need to do to make things right.

Thanks