2003 Johnson ST 6/8 HP 4 Stroke Outboards Service Manual, PN 5005471, Page 99Get this manual
FUEL SYSTEM FUEL PUMP
Carburetor
The carburetor meters and distributes the fuel consumed It controls engine speed and power output by varying the intake charge densityTo react correctly to wide range of operating conditions, the carburetor has multiple fuel mixing circuitsMixture enrichment for cold starting is controlled by choke
FUEL PUMP
General
Before replacing suspect fuel pump, remove and clean the fuel filter and install new filter elementAlso, remove the fuel hose from the fuel tank and blow through all passages and hoses with low-pressure compressed air to be sure they are openThis might be the cause of inadequate fuel deliveryIf this procedure does not correct the trouble, test the fuel pump