1997+ Mercury 35/40HP 2 Cylinder Outboards Service Manual PN 90-826148R2, Page 141Get this manual
Reassembly Check Valve Assembly
1Insert retainer (a) thru plastic disc (b) and rubber check valve (c)
3With retainer installed in pump body, bre ak retainer rod (a) from retainer (b) by bending sideways
23601etainerPlastic DiscRubber heck Valveetainer Rodetainer