Welcome to the forums. I agree, it's probably a stopped up carb. Remove the carb and remove the float bowl. Remove the float and float valve and clean the float valve and the hole where it seats. Remove the main jet and slow jet and make sure the holes aren't clogged. Hold them up to light and make sure you can see through them. You will need to remove the pilot screw, but before removing, turn the screw all the way in to a lightly seated position, while counting the number of turns it takes. Do not tighten or you will damage the end of the pilot screw. Just turn it in until it stops (lightly seated). Remember the number of turns so you can put it back to where it was. Be careful not to lose the tiny o-rings, spring, and tiny washer on the end of the pilot screw. Most of the time the o-ring will stay down in the hole and you will need to dig it out.
With the pilot screw, both jets, float, and float needle out; blow carb cleaner or air through all of the passageways in the carb body to make sure they aren't stopped up. Don't forget to blow air through the carb bowl inlet and out the float valve hole. Clean any debris out of the carb bowl.
You don't have to remove any of the choke parts and you shouldn't need any special tools. Make sure you don't spray carb cleaner on any of the plastic or rubber parts, such as the o-rings. Carb cleaner will dissolve plastic and rubber.
Now you can put the jets back in and the float and float needle. Put the spring, washer, and o-rings back on the pilot screw and turn the pilot screw all the way in to the lightly seated position. Now, turn the pilot screw out the same amount of turns that you counted when you turned it in earlier. That will put the pilot screw back to it's original position. Put the float bowl back on and reinstall the carb.
Most 4-wheeler problems are caused by a loose nut connecting the handlebars and the seat!!
You only need two tools in life -- WD-40 and duct tape. If it doesn't move and should, use the WD-40. If it shouldn't move and does, use the duct tape.