1987-1993 Mercury Mariner Outboards 70/75/80/90/100/115HP 3 and 4-cylinder Factory Service Manual, Page 113Get this manual
Acceleration Pump Circuit Operation Four Cylinder Engines ACCELERATOR PUMPReceives pressurized fuel from T-fitting in fuel line between #1 and #2 carburetorsPump is actuated by throttle camPumps to two check valveinjector nozzles in #3 and #4 cylinder boost passagesFUEL FILTER74 micron filterPrevents debris from plugging check valveinjector nozzlesCHECK VALVEINJECTOR NOZZLEassemblies, one each for #3 and #4 cylindersFuel passes from check valve thru .026 inch orifice (injector nozzle) and into respective cylinder boost passage
FLOW RESTRICTORHelps equalize pressure within the accelerator pump circuit while allowing air or any vapor which has formed to pass through and be vented at the carburetorsFUEL CONNECTORSpring loaded shut off valve which connects boat fuel tank with outboard fuel systemIMPORTANT: The distance between the accelerator pump and the throttle cam determines the amount of fuel the accelerator pump will dischargeIf accelerator pump is moved or replaced, refer to SECTION 2C for correct positioning of accelerator pump