Why much higher fuel consumption?

[TomTom]

My 1967 Amazon is guzzling fuel since having a tune-up. It's gone from 220 miles between 33 litre fill-ups (about 25 mpg)to barely 110 miles.

I have checked that the pistons are going all the way up when the choke is pushed in. Is there anything else I should check?

The Haynes manual suggests sticking/broken needle. Would that be a likely cause?

The other symptom is that the throttle is over-responsive, and it seems that the car shoots forward a bit too quickly.

Any ideas would be gratefully received and if anyone knows a very good carb tuner in SE London, please post the details. Thanks.

Tom

[mike gilbert]

One thing springs to mind. When you mean the pistons I presume your referring to the jets which move up and down with the choke cable. With the jets in the 'up' position, in other words with the choke fully pressed in, look inside the throat of each carb to see if the top of the jet is level with the brass ring it sits inside (you can watch the top of the jet descend and ascend as someone pulls the choke cable out and back in). If it is still below the level of the brass ring with the choke pressed in the carbs will run rich.
Mike Gilbert