Yeah, old fuel works well for dissolving the goo, but if it's been sat for long enough, I'd say the bearings would have corroded, especially if it was just stored without any preventative measures. I usually knock the head and blackplate off so the fuel can get in everywhere, and when you want, it can get out again easily. Once it's all moving freely again, have a look at the rear bearing (easy to see) if it looks nice and feels nice, go play. If it looks rusty and feels like it's got sand in it, replace both.

One final thing, before you run it up (and i've seen/heard too many people NOT do this) flush your carb out to remove any gums, bits of fluff or debris. It should be SPOTLESS before you even think about firing that 40 up.