Mercury Mariner V-250 V-275 Outboard Service Shop Manual 1990, Page 79Get this manual
RemovalDisassembly IMPORT ANT: Fuel pump diaphragm and gaskets should not be re used once fuel pump Is disassembled1Disconnect fuel lines from fuel pumps2Disconnect pul se hoses3Rem ove two mounting screws from each fuel pump
CleaningInspection
1Clean fuel pump housing, check valves, pulse chamber and pump base in solvent and dry all but check valves with compressed air2Inspect each check valve for splits or chips3Inspect boost springs for weakness or breakage
4Inspect fuel pump housing, pulse chamber and base forcracks or rough gasket surface and replace if any are found 5Inspect fitting on fuel pump housing for looseness or any signs of fuel or air leaksReplace or tighten fitting if leak is found