25 HP Force acceleration problem

I have a late 90's force 25 HP triple cylinder single carb. I'm having acceleration issues with it. When I get it running at a stable idle then put it in forward and try to accelerate at a moderate speed, it burbles and stalls. The only way to get it up on step is to accelerate very very slow. Then when it stats revving up, it works fine at medium and high speed. My problem is a the low end, and it's very frustrating. I have asked my mechanic about it and he just says it's cause you have one carb feeding three cylinders. I find this hard to believe that this has been an inherit problem with this motor. I'm hoping that I can resolve this problem with an easy adjustment. Thanks

Did it just start? Has it been setting up awhile? The baloney about the carb and 3 cylinders is just that "baloney". Sounds like a carb problem maybe a restriction. Possibly a fuel pump. Although it could be a number of things.