Carb problem? I think

I have just purchased a M38A1 its been converted to 12 volt and has a carter YF carb on it and when in high range 3rd gear running up a slight grade it will run ruff I thinks its the carb. I thought it might be the float adjustment but I double checked the float adjustment . The carb has just been rebuilt buy a highly recomended shop I have installed a new distributer checked the timming ,plugs and plug wires . Can it be the carb is passed being able to be rebuilt? Should I replace it ? if so what carb do you recomend?

 

If I were to speculate it would be that the fuel pump (vacuum pump) the little glass thing, has poor suction. There's a way to test it, but I'm not sure how since I just replaced mine.

 

Check for vacume leaks. They can be very pesky to find as this thread shows
http://www.earlycj5.com/forums/showthread.php?t=29268&highlight=Carb+base