1988 45hp stalls when put into gear

[imported_hotrod]

1988 45 hp 4 cly serial # ob356219 had problems with it it idling rebuilt the fuel pump and changed the squeeze ball,fuel filter now it idles fine its when i put it in gear it has a tendency to stall will always restart so far. to get it going i have to put in gear with higher rpms i know this can't be good.also how does the carb get air the top seems very tight with no vents even with top off it stalls.i did buy a seloc manual. thanks again for help with the fuel pump one of the springs were missing