2001 Yamaha Wolverine - Running Bad

[gatorchin]

at the end of last summer, i had re jetted the the carb on my 2001 350 wolverine...i can't remember exactly what the stock size was, maybe a 143 or so?? but i know i put a 147.5 in it...that it..stock air filter, exhaust,etc..anyway, near the end of august and september i had that baby dialed in...once it warmed up, it had great throttle response, more power, and was running like a top...i had some issues with my electric start, but that's for another thread (actually i think there is another thread on here about that problem)..so here comes winter...all winter long it ran like crap, and still is..it wont idle very long before it just stalls out...sometimes when i put it in first gear and try to pull out, it stalls...sometime i can ride it down the road a ways, and if i let off the gas or come to a stop, it stalls....it has a little backfire to it as well..not real loud, but i can hear it inside the carb..now somebody told me that jet size was too big, especially in these colder conditions....somebody told me i had bad gas (water)...thing is i filled it up and have been on that same tank all winter long, becuase i haven't riddden much, mostly due to how it has been runing...i am thinking of selling it and getting something bigger, so i want it to be running like it was last summer...so should i put the stock jet back in ??? should i drain the gas and put new gas in?? or both??

[oxidized_black]

it will be easier to dump the fuel and put new in and see if that helps, if not maybe rejet ... how are the valves ?? set to the right valve lash ?