My 2012 60hp efi four stroke merc fuel cap went bad(cased a vacuum) and caused my low pressure fuel pump to go out. Before realizing cap was bad I replaced ALL fuel lines fuel filter and took the vst apart and cleaned it as the pump going out sent small partials to it. Low pressure runs around a $100.(my 60hp)$4 ft for marine fuel line, $14 for fuel filter and cap was $49 and a lot of headache as well. If your motor is a merc and you clean the vst watch the wires and gasket as you put it back together as the wires if run wrong will interfere with the float(don't ask) and the gasket will leak if not lined up correctly. Hope it helps and good luck.
May all the fish tales you catch be longer than the ones you tell !