Your problem is definitely carburation. These are not bad little carbs and the thing merely needs cleaning-out (these devices live in an aggressive environment and old fuel tends to varnish/gum them up over the Winter). Basically clean-out every orifice and jet that you encounter - especially the emulsion tube etc. Use an airline where you can - and if necessary a broken wooden toothpick/cocktail stick on the larger orifices. You may find a bead or two of water in the float chamber and/or the float sticking too. Get rid of the contaminated fuel in the float chamber, free the float as necessary, and carefully wire brush [or wet and dry paper] away any corrosion which has occurred within the float chamber bowl etc. GOOD LUCK!
The Mainecoon
June 2010