1997 Johnson Evinrude "EU" 9.9 thru 30 2-Cylinder Service Manual, P/N 507263, Page 64Get this manual
Description of Fuel System
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
rn 2Theengine speed and power output bythe fuel consumedcarburetor meters and distributes It controls varying the intake