Installing a Diesel Priming System on Your Boat
Story and photography by Capt. Vincent Daniello
If your priming pump won’t build enough pressure or doesn’t push enough volume to get the air out of your filters, or you just need to speed things up, you’ll have to vent air from fuel lines at key places. (Some boats with long, small return lines or a large drop between engine and fuel tank won’t prime themselves unaided, a condition that may also be dependent upon how empty the fuel tank is.) With the priming pump on, crack a fitting or open a bleed screw at the top of the secondary fuel filter—the one mounted on the engine. First air will seep out, and then bubbly fuel. Once fuel flows clean, tighten that fitting while the pump is still running.