fuel injection part 2

[Alan Pritchard]

well ive determined that my system is far too rich... this is probably due
to the removal of the gauze filters.  i determined this by disconnecting the
vacuum line from the pressure regulator which improved things marginally,
also all my plugs are very sooty, and the car stinks of unburnt fuel....
so, how do you go about changing the fuelling throughout the range, i guess
its due to the spring loaded needle valve that slides into the front of the
fuel head.
any additionalo info on the subject would be very useful