Where does your exhaust exit?
Yes it could be rich, could be exhaust leak, or could be like mine exiting before rear tires...
You can try adjusting carb a little, if it runs good though, mark where the screws currently are or track number of turns you adjust in cas you need to go back. Easiest way to do this is to take 2 small 3" fuel line pieces (5/16 i think, will check later today) that will fit snugly over the mixture screws. Then mark the 12:00 position and turn the screws with the hose ( no screw driver required

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Also you can check the condition of your spark plugs as well to note how they look...