I think you have the rod diameters crossed with the rod designation........Say you were going to butt weld 4 " carbon steel pipe-std. wt.-using SMAW, then you would probably use 1/8"-6010 for the root pass and 3/32"-7018 for the balance (fill & cap).
I usually set my machine around 78-82 amps (DCEP) and I can burn those rods just fine all day long.