1998 Johnson Evinrude "EC" 150, 175 FFI Service Manual, P/N 520211, Page 37Get this manual
The vapor separator receives fuel from the filter canister, then supplies fuel to the electric circulation pump for distribut ion to the fuel rails and fuel injectorsA water hose from the base of the powerhead on the port side connects to the bottom of the vapor separatorWater flows upward to cool the fuel, then exits the separator through hoseand is routed to the starboard rear of the powerheadIt's teed into hose coming from the top of the powerhead and discharges into the base of the powerhead The water cavity is self-draining when the engine is shut offThe fuel chamber can be drained by removing plug from the bottom of the port side of the housing
[] Return fuel from the injectors is routed to the top of the separator and through the fuel pressure regulator The regulator maintains system pressure at approximately 20-30 PSI (138207 kPa)
in the port intake manifoldVapor pressure and low vacuum at