I have a new 2019 Dongfang DF50TKC trike. I cannot get it to idle right.......its too high or too low and stalls, I just cant find that sweet spot. So have to carry my trusty phillips screwdriver and adjust it during my ride. Does this carb have an automatic choke? I dont have a manual lever anywhere that I can see.....or is it the time of year (chilly) that effects the idle?