Its no good just swapping the needle without setting the base mixture at idle, did you do that after the needle swap? set the new needle to 2.5-3.5CO at idle
Just looked at the needle charts and the AAU needle is richer just off idle and very much so from position 7 on the needle chart, are you able to check the timing yourself? if not then I'd stay away from the previous mechanic and find one who understands basics about distributor ignitions and setting up SU carbs.
You need to make sure the engine is setup correctly before trying to do any carb mixture setting and thats points/plugs/timing/tappets, but with out equipment like a rolling road its all down to experience and thats the hard bit
Quote from Mini Spares on the AAU
The favourite and best needle for Minispares stage one kit. Tested on a rolling road by Peter Baldwin and Keith Calver this baby gave the best performance when using our
RC40 system, Minispares inlet and exhaust manifold plus a K&N filter.
If using other manufacturers components this needle never seemed to work as well from results obtained or given to us over the last 5-6 years, but it is a good starting point.
Edited by KernowCooper, 13 March 2013 - 06:26 PM.