Well this problem has been going on since the middle of this winter. So when i go out and try to start my atv in the cold ( 32 and anywhere below) it doesnt want to start very well. so i put the choke on it a couple turns later she starts. I let it warm up for about 2 to 3 minutes and think its ready take it off choke and it barely keep running. I put it into gear and it putters and seems to be miss firing. Had it up to a machanic and he looked it over but only thing he found was the exaust valve was loose. I just rebuilt the carb so im not really sure what is wrong with it. Should i just not use it on cold days or just let it run on choke longer like 5 to 8 minutes? Please if there is anyone with any ideas pls help me out on this. Also it never did this in the beging of this winter so idk.

 

Cold weather makes em run lean! Same thing on my Honda street bike even after I jumped the pilot jet up one size. You can lower the clip on the carb needle(which raises needle) which may help a little,plus depending on your model you either have a fuel/air screw(at the front bottom of the carb) or an air fuel screw towards the rear of the carb. If its at the rear you can turn in say a half turn and see if it helps(slows down air allows more fuel) If you have an air fuel screw and if its not blocked off,you can turn out in 1/4 turn increments to allow a little more fuel to the idle(pilot jet) and see if it helps on warm up. Not really a good idea to just let it sit with the choke on as plug fouling can happen. Or you can do like I do on my cold blooded Honda,just drive off under partial choke until you can slowly let off the choke as it warms up on cold days. OPT

 

Ok well ill try and see if moving that fuel/air screw does anything when trying to start it. Would u have any idea what the miss firing sound would be? cause after its warm it doesnt have the miss firing sound but when u first start it it does and when u take off it putters like it wants to die but i push the throttle hard and it comes back to life. any ideas?