Some ATV's are just cold natured no matter what. I know when I used to have a 400ex that it would just NOT want to start. Even in 50 degree weather. You might as well expect to use the choke when starting in temps that low, I always have to as well.My 07 Rancher AT GPScape is Very cold natured. When operating in temps around 20degF hard to start and have to choke every time you restart even when engine is warm. any suggestions???