Mercury 75 Service Manual page 189

Acceleration Pump Fuel Flow Circuit for Four Cylinder Engines
#1
CARB.
+4 .5 PSI
#2
CARB.
#3
CARB.
#4
CARB.
NOTE: Fuel pressure values are approximate.
90-830234R3 DECEMBER 1997
+5 .0 PSI
+4.0 PSI
CYL. #3
CHECK VALVES
LOCATED IN
CYLINDER BLOCK
TRANSFER PORTS
(UNSEAT AT 11–14 PSI)
CYL. #4
BRASS RESTRICTOR
(.014" I.D.) LOCATED
INSIDE FUEL LINE
ACCELERATOR
PUMP
SMALL
FUEL
FILTER
+3 .5 PSI
FUEL
PRESSURE
DROP OCCURS
–0 .4 PSI
LARGE
FUEL
FILTER
+5 .0 PSI
FUEL
PUMP
–0 .5 PSI
FUEL
CONNECTORS
FUEL
TANK
FUEL SYSTEM - 3B-27