why not try some decarb product like Mercury Power tune or equivalent Evinrude product or splurging $$ on a carb which has little probability of failure unless physically damaged.
Secondly try another pressure meter or run the RPM higher with a drill to test PSI….
I doubt crankcase vacum would be so low as to cause poor fuel pump operation
anything is possible but do the easy stuff and cheap stuff first
Joining AOMCI has priviledges 🙂
