engine keeps loosing its fuel prime

hi,i went to the lake with a bass boat today it has a 75 merc 2 stroke engine its carbs was cleaned by a certified dealer 3 days ago , ran great with a hose but when i launched it today it woundnt stay running lack of power but if i kept the fuel bulb primed it would run for a short burst then stall, again i would prime it and it ran good for a minute or two , i looked but didnt see any gas leaks, has any body had a problem like this ?