33 dellortos problem

[jonathan coates <alfa@domain.elided>]

My 8V 1.7 33 QV wagon has developed a new foible and soots up the right
rear spark plug. If I take the air filter assembly off I can see fuel
dripping inside the venturi which isnt happening on the other three. At
wider throttle settings all four carbs drip from the same point.
Is there an adjustment which needs to be made or are the carbs in need
of rebuilding? I recently had the carbs balanced and the engine ran
sweet for a few weeks so I'm wondering if there is a locking nut which
wasnt nipped correctly.
The dripping comes from the small circular cast bit (venturi?)in the
middle of the casting which spans the bore of the carburettor.
On the Cardisc manual the equivalent (looking) part is the auxilliary
venturi inside a Weber carb if this helps.
- -- 
jonathan coates

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