No I didn't miss the point; of course I ensured the tap was working; of course I ran the engine dry as you would do in say a two stroke lawn mower, but as others have posted that's not enough when ethanol or methanol are present. In racing, where the fuel is methanol the current practice at the end of the day's racing is to turn the fuel tap off, run to dry carb, connect a can of about half a litre of petrol to the carb and run the engine until that's gone through.
I've also followed the practice of taking all the carbies off after racing, shaking the last drips of fuel out and submerging them in a tray of [ethanol-free] petrol until the next race.
With ethanol; if you don't want to be trying to clean out ethanol powder or solids blocking galleries which you can't get to with probes, compressed air or boiling the whole carb for a couple of hours, you don't use any petrol with methanol in it.
Skippy talks about Rotax and ethanol tolerant engines and it's true that some carbs are manufactured by CNC drilling galleries and having screw plugs each end so you can open these and run a twist drill through the galleries with your fingers and ream out the solids, so not have any further issues; Rotax my have other solutions.
However, this is not a Rotax site and there will be thousands of Ultralites around Australia with carburettors of all descriptions which have been designed for cost and can't be cleaned out. In most cases new carbies are available; in others there are no new replacements available and no used ones in wreckers so you have to junk the engine.
With Ethanol the rule is pretty simple; if you don't like trying to clean out erhanol problems from the