Hey man i have the exact same atv, 2001 350 warrior stock motor and pipe, and experienced the same problem after putting it in storage for a year. It isnt normal at all, and is easily fixable, you will need to remove the seat, plastics and gas tank so you can get the carb off, 12mm wrench, some allens, and 10mm + 12mm sockets will be needed. To remove the throttle cable it has like 5 screws (philips) with a black cover once that is off you will see the cable just unhooks and will slide out the cable hole. Put the carb on a table with some newpapers and scott towels down and spray the outside down with carb cleaner so when you open it, crap doesnt fall in, their is a hose at the very bottom of the carb with a screw just above it, loosen the screw so the gas all drains out then you will need to remove the "bowl" its at the bottle of the carb and has four screws (philips). You will see a main jet and pilot jet, now the main jet has a disk like thing on it note the direction it faces and remove it then remove the jet with a flathead throughly clean the carb and all jets with carb cleaner then reassemble. Now find the fuel mixture screw its on the side of the carb ( shows in manual) and turn it all the way in, then back it out 2.5 turns <-- this is crucial dont skip it! Reassemble the atv but completely drain the gas tank and put a new hose on it with a fuel filter (1/4) they sell them at places like pep boys if you dont have a local dirt bike shop. The reason for this is because from sitting the gas has caused varnish to develop on the walls of the tank and will continue to just clog the jets on the carb, the fuel filter works amazing and is like $3. I reccomend using 93 octane gas also. Good Luck & Hope This Helped!