Mercury 35/40HP 2 Cylinder Outboards Service Manual PN 90-42794--1, Page 61Get this manual
Fuel Pump with One Red Colored Check Valve and One Black Colored Check Valve IMPORTANT: Red colored check valve (a) must be installed in the intake side of the fuel pump as shown1Install check valves and new gaskets into fuel pump2Secure check valves in place with check valve retainer (d) and spring retainer (c) 3Place spring (f) into spring retainer and place cap (e) onto spring Fuel Pump with One Red Colored Check Valve, One White Colored Check Valve and Filler Block
1Install spring (g) into filler block (e) by placing spring into hole and pushing down on spring (compressing) while turning spring in clockwise directionTurn spring in until it bottoms out