In that case it is likely you are not sticking the tip of the rod in tight enough. I like to keep a slight drag on it and prefer to keep the tip in close the whole time. If you start putting weld on the bevel faces rather than between the lands the pipe can close up on you.
If you are jerking it off, forward and back, you may be going too far foward or not coming back soon enough... you could try not less movement.
An 1/8" root is plenty... an 1/8" land is pretty heavy, especially for a 1/8" rod. Personally I like 3/32 x 3/32.
More current couldn't hurt. If you have a dig control on the power source you may want to turn it up.
Regardless pene is all about maintaining the keyhole. If you don't have a good keyhole, for goodness sake change something - don't keep welding or all you will accomplish in another bad root.