Nissan Repair: Carburetor Modification after changing from automatic to mannual Transmission, poor mileage, nissan sunny

Question
I own a Nissan Sunny B13, 1990 model, 1290 cc engine capacity. The first owner changed it from Automatic Transmission to Mannual. It now has a very poor fuel utilisation doing only 9km per litre. What Carburetor modifications/adjustments are necessary when such a car is changed from Automatic to Mannual Transmission.
Thanks for your time and support. Leonard.

Answer
Leonard,

I do not think it is the swap that has caused a reduction in mileage.  Check the power valve and see if you are not hurting due to it being defective.  The power valve looks like a small brass pipe in the bowl that has two electrical wires that come off it.  If you are runnign as rich as you say that would be the cause of the poor mileage.