Mercury Mariner 30/40 4-Stroke Outboard Service Manual 1998, Page 143Get this manual
FUEL PUMP
Fuel Pump Operation
1The fuel pump is diaphragm pump which is mechanically driven off of the rocker arm2The black mounting block (insulator) and the two outlets on the fuel pump help prevent vapor lock3If the engine runs out of fuelor has restriction preventing adequate fuel flow, the pump will make uclicking" noise
SMOKINGBefore servicing any part of the fuel system, system at the batteryDrain the fuel system completelyUse an approved container to collect and store fuelWipe up any spillage immediatelyMaterials used to contain spillage must be disposed of in an approved receptacleAny fuel system service must be performed in well ventilated areaFUEL LEAKAGE FROM ANY PART OF THE FUEL SYSTEM CAN BE FIRE AND EXPLOSION HAZARD WHICH CAN CAUSE SERIOUS BODILY INJURY OR DEATHCareful periodic Inspection of the entire fuel system is mandatory, particularly after engine storageAll fuel components, including fuel tanks, whether plastic, metal, or fiberglass, fuel lines, primer bulbs, fittings, swelling, and must be inspected for corrosionAny sign of leakage or deterioration necessitates replacement before further engine