1987-1993 Mercury Mariner Outboards 70/75/80/90/100/115HP 3 and 4-cylinder Factory Service Manual, Page 89Get this manual
Troubleshooting Fuel Pump (continued) PROBLEM: LACK OF FUEL PUMP PRESSURE Possible Cause Corrective Action
Fuel Pump Components (Design 1)
NOTE: In fuel pump reassembly, remember that respective diaphragms go against the mating surfaces of the fuel pump body, and respective gaskets are between the diaphragms and end capsGaskets should always be replaced on fuel pump assembly
Hole in pulse hose (1 pulse hose)Loose pulse hose
Replace pulse hoseTighten connection
Boost diaphragm gasket Check seal between distorted or out of placemating surfaces where "rib" divides pulse chamber gasket must align with rib; check for distorted gasketAlign or replace gasket if necessary