Thanks to you all for all the advise and help but it seems I have destroyed the rubber tip on the needle valve so they don't seal any more. New ones only come in a kit with the seat, O ring and spring and cost £37 each Four required... AAAAAAAAAAAARRRRRRRRRRRRGGGGGGGGGGGGGHHHHHHHHHHHHHH

Steve

Was this after you soaked them in solvent/acetone/cleaning fluid?

Steve.

Hmm I used cellulose thinners but didn't keep the rubber tip of the needle away from it. Also thinking the needle valve seat was pressed in didn't count on there being a rubber O ring under it. Result: needle vavles not cutting off the fuel when the float level is correct and pumping up through the spray tube and into the venturi.
It's painful man I tell ya!

Steve