1993 Johnson Evinrude "ET" 9.9 thru 30 Service Manual, P/N 508282, Page 61Get this manual
Description of Fuel System r:;l 1The fuel pump is of the diaphragm-displacement type and is operated by changes in crankcase pressureAlternately, suction and pressure in the crankcase are transmitted to the pump diaphragm
2The carburetor meters and distributes the fuel consumedIt 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 circuitsstarting is controlled by either choke (9.915 ), manual primer (rope and TE models), or fuel primer solenoid (remote control models)