I doubt the "pulsing" of the fuel pump would have any effect - after all the caburetter is designed for it, although it does strike me that since it is a new pump, is there any possibility that it is the wrong one? In particular the diesel one is identical - except that it has a much more powerful spring (which is what actually delivers the fuel) and if it is the wrong pump the fuel pressure will be too high.
The problem with this engine is that when it was designed, fuel consumption was about at the bottom of the list of desirable features - it was designed for flexibility, durability, and tolerance to lousy fuel. Add a vehicle with zero attempt to reduce aerodynamic drag and a large frontal area, plus a drive train designed for ruggedness and simplicity, and you have a recipe for high fuel consumption. The only thing that could have been done to make it worse would have been to try and get high performance as well (see Stage 1 or even the six!).
Apart from getting everything working properly, the most effective way of improving fuel economy will be to increase the compression ratio, particularly if you have a 7:1 head. This is relatively cheap and simple, and will have only a minor impact on flexibility while improving maximum power, and should yield a modest decrease in fuel consumption provided you do not make full use of the extra power. (some models had an extra spring that came in at half throttle - I haven't tried it, but it is said to be effective)
John
John
JDNSW
1986 110 County 3.9 diesel
1970 2a 109 2.25 petrol
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