1998 Johnson Evinrude "EC" 150, 175 FFI Service Manual, P/N 520211, Page 36Get this manual
The lift pump is diaphragm operated device driven by crankcase pulses from cylinders No.1 and 4It draws fuel from the boat tank, and directs it to the filter canister at the back of the powerhead at approximately 2-10 PSI (13,8-69 kPa)The pump chamber has flexible diaphragm, and inlet and outlet check valvesThe diaphragm alternately expands and contracts to draw fuel from the tank or push it to the filter
INotel damaged lift pump is not capable of maintaining FFI system operation
Circulation Pump
The circulation pump is electrically operated, and controlled by the ECU through relay in the Power Distribution PanelIt draws fuel from the vapor separator and supplies it to the FFI systemIn key onengine off situation (no tach signal), the pump will operate for only 10 seconds, then stopIf the engine is cranking or running, pump operation is continuousShould the engine suddenly stop running but the key remain on, pump operation will continue for 10 seconds before stoppingPump operation will stop immediately any time the key switch is turned off