My son has a 2000 Warrior 350. It sat for almost a year without starting. We drained everything and cleaned it up as good as we could and then refilled all fluids. It ran fine for a couple days. It still starts perfect everytime with choke all the way out. Even after warming up it stops everytime you push the choke in. He has been riding it with the choke pulled out a little but it idles very fast that way. Any reasons why it wont keep running with choke in? I tried running some carb cleaner thru it.

 

The carb jets probably need cleaning. Need to take the bowl off of the bottom of the carb and take the jets out and clean them. Put Sta-Bil in the gas next time it sits for a while. Crank the engine and let the Sta-Bil circulate into the carb.

 

I agree with Raptor450, carb needs a good cleaning and fuel shutoff filter(if equipped).