2000 yamaha 50hp carb issues....

Hey, my motor won't allow the boat to go over 3-5mph,it bogs down. If I give it more gas,it will cut off,(restarts ok). It will rev up high rpms,at idle when not in gear,as soon as I put it in gear,bogs down. Before I attempt rebuilding the carbs,I wanted some insight.
In addition,I can't find a carb-rebuilder in my Oceanside N.Y. area,If anyone knows someone,that'd be great too.
THANKS