Well, It's got nothing to do with your CV carb diaphrams, your mate may have been referring to vacuum operated petcocks which, if the diaphram is damaged, can flood carbs.
Most CV carbs don't have drains like proper slide carbs, so the fuel will run into your engine, or out of your airbox when the float valves eventually become overwhelmed by the amount of fuel trying to make it's way in, which is another good reason to turn your fuel off.
Even with slide carbs with drains this can happen, if the drain tubes become clogged. Don't try to start it, the gas has already washed the lubricant off all your bearings and gears, so while it may not actually explode, it's gonna ruin your whole engine and gearbox if you're silly enough to try to start it.
Dump your oil and filter, (the oily gas mix makes a very good weed killer) and let all the gas drain/evaporate before refilling it with nice fresh oil And look on the bright side, at least the engine will be nice and clean now that you've "degreased" it's internals, ha ha! Cheers, Terry.