My 90 fourtrax 2wd is frustrating me. I bought a new carb and installed it. Adjusted the idle mixture screw. It idles fine and accelerates fine but when I’m riding around the yard at slow speed it spits and shutters and sounds horrible. Its a new carb but I still removed the jets and they look fine. I put a new spark plug in it and it still runs the same. Can someone please help before I send it to the bottom of the lake? Just kidding but seriously need some help.