A small amount of water in the float chamber can cause havoc with jets since the fuel tends to float on top of it. So maybe one carb was getting some water ingress through the choke mechamism which is open to atmosphere (hence the wooshing noise).
Neil
JUust realised how much I miss the characteristic "Whooshers" now that I have Dellortos and an electric priming pump fitted.
Must admit I didn't realise that's the reason why they make that noise
Brian
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