Also worth checking the sync of the throttles - I think only one body has TPS so if the other one is out of sync it may cause the problem. DO you have an airflow meter (either vacuum gauges or the weber flow meter)? If you do you could increase the idle on the throttle stop and then check the airflow in each TB.
Super happy chappy thanks all for the input, nice easy fix. Must have been dragging air in, messing with the mixtures.
First glance the quick release pipe looked locked in, surprised it didn’t pop off to be honest,must have been the flow/feed and starving dropping pressure. Was letting just enough fuel through when pump running.
