I have a 99 Johnson 50hp 2 stroke. When I first got the motor last year I had to replace the computer. I also did the spark plugs and all fluids. It has run great except for one thing. When I put it into forward gear just above neutral it will stall out after about 45 seconds to a minute. The engine will vibrate some and just die. I need to go slow in the canals in Winter Park. All else is well. I think maybe I need to clean the carbs? Would this help?