Mercury Optimax Models 135, 150, Direct Fuel Injection., Page 145Get this manual
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, chips and for proper sealing against pump housing3Inspect boost springs for weakness or breakage4Inspect fuel pump housing, pulse chamber and base for cracks or rough gasket surface and replace if any are found5Inspect fitting on fuel pump housing for loosening or any signs of fuel or air leaksReplace or tighten fitting if leak is found