I bought a used 2009 sportsman 500 H.O. and it ran fine for a while but now it bogs down and spits and stutters going uphill when I’m giving it more throttle. I cleaned the carb and the jets, changed the air filter and checked the fuel filter. Spark plug could need changing but its not that bad. I also put in new gas. It idles fine and on level ground does fine. Sometimes I can go uphill slow and steady with not much throttle and it’s ok. Other than waiting on the spark plug to come in in a couple days I’m not sure what else to try.