ABS settings for 8" i3 with .35 j-head

[st5k]

ok so im having issues with finding the "sweet spot" for PLA on my printer.... right now 183 for the print head and 65 for the bed is ok, but it seems to me that i may still be doing something wrong... there are several print that come out good but others im just not sure why they turn out the way they do... for example the print will look great till about 1 cm up then all of a sudden the bead starts to roll off a bit and get stringy... will a fan maybe help this? am i not giving the layers enough time to cool?