I need help with a 1997 bombarier sea.doo gtx?

I bought this sea.doo and when i put it in the water it woulnd run at a idol. but when you give it gas it bogs down and tries to stall. I put it in the shop and they clean the carbs and they clean the fuel system. and they tested it in a tank and they said it was fixed . but when i put it in water agian it would go at a idol about 6 mph same as before but nut when you gas it . but will go about 40 to 45 if you pull the choke out about 1/2 of an inch. what could be wrong with it ?