We have a 2006 Yamaha bruin 350 2WD we have put a new OEM carberator on it thinking that was our issue turns out it still sputters out. We have adjusted the idle screw thing(forget exact name) and it did not seem to help. Sometimes we can start it and it will sit and run fine but then after it's warmed up and your going it will start to sputter some while driving. If you down a hill it will act like it is completely dieing all together and losing power even after depressing throttle pretty far but eventually will kick back and go and continue to do this over and over going down an sort of slope. Also sometimes when you try to choke it it will kill it and then sometimes if its running with choke it acts like it's not then if you turn the choke off it acts like it was turned on and idles higher and if you try to go from neutral to forward it will jump you forward.I need suggestions on what the heck may be wrong as it is very annoying trying to spray my fields and dealing with it wanting to sputter out and die. Thanks in advance for any help I just want it fixed.