I have a switch mounted on the overhead, above the 1/4 berth in my Catalina 27 which was repowered before my purchase, with a 3GM Yanmar. When I flip the switch there is a whirring sound....could it be an electric fuel pump, I see an inline small cylinder looking thing with power to it in the fuel line. For bleeding? Not a clue when it comes to diesel.
Love the extra HP though.