Yep - the carbs will need cleaning out. Sounds like the pilot jets are gummed up, and possibly the needle jets too. And obviously the corresponding airways. Given the amount of time ultrasonic cleaning would be best, but carb cleaner would be a start if you know what you're doing. It's safe to assume you don't but we all gotta start somewhere & we're happy to help 
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Either way they'll need removing - just spraying carb cleaner into the airbox or bell-mouths will do nothing other than just push the dirt around.
I have to say also that running an air cooled engine, revving on choke, with no forward movement & hence minimal air cooling is a pretty dumb idea.
Standing for so long will probably also mean the fuel tank has starting corroding inside. At the very least it'd be a good idea to flush it out and fit an inspectable, replaceable inline fuel filter between it & the carbs. It might well need sealing - use POR15 products rather than Petseal (it's crap).
If cleaning the carbs doesn't totally cure the problems, and rust from the tank isn't clogging fuel flow (and gunking up the carbs again) then you may also need to replace some ignition components. This winter was pretty mild, but the previous couple were quite harsh and condensation combined with freeze-thaw action can break down electrical insulation.
Anyways, as I say, we're generally happy to help, but only if you pay attention to advice!
arrrf.
