Well if it's lean you can pull a spark plug and it will be white. You want a light brown/ish color on the plug. A fuel injection pump will feed plenty of fuel to a carb motor but would require a regulator(I have done it before). This is assuming the pump is working right. I have had electric pumps that would work but not supply the correct pressure(low). Just had a walbro electric pump on my brothers street car do this exact thing.