Sounds like a low speed jet trying to plug up. If you have a filter on it check that first. But I would get a can of seafoam from WM and put 1/2 can to 6 gallons of gas and run it on muffs for 20 min, let sit overnight then do it again and let it sit. Then take to lake and run the stew out of it for awhile. That should clean it up.