Thanks Gerry, I'll put the carby back and try that. At your suggestion, I very carefully wiggled the emulsion tube out (I can understand why you said to not turn it with a screwdriver in the top - there's a little lug at the bottom which sits in a groove and this could be damaged or broken, as you said.) It took a while to get it out as it was pretty tight so I don't think there would be any leakage there. Anyway, I'll Loctite it back and try your pump suggestion. Thanks again for your helpful hints.
Rod
Rod