I recently bought a New Holland 273 baler with thrower and it works great except for one knotter.  The inside knotter (right side) ties a perfect knot every time.  The tail is about 3/4" long when the knot tightens up after the bale leaves the chamber.  The other side is about 3/8" long after the knot tightens up and it will pull apart when if you get a heavy bunch in, or if the windrow gets thicker.  I've tried loosening the twine holder tension as was mentioned to me by several folks, but it didn't seem to make much difference.  I went about 1.5 turns looser on that side and the length only increased to about 1/2" on the tail.  Do I need to loosen it more, or is there something else I need to look at?  The knife arms and knives are all brand new, replaced by the dealer I bought it at.  They are adjusted exactly the same as the knives line up perfectly when viewed from the side.  The other night when I baled, I missed about 40 bales in 250, and today I missed 6 in 140.  Two of those had at least one twine burned off by the thrower, though I don't know if it happened because the one knot let go, or because the bale didn't get pulled right by the thrower.  I am running plastic twine 170lb knot strength.  Baler had sisal in it when I saw it at the dealer, they switched it to plastic for me.  Anything else to check?  I used to have an old International baler wtih the McCormick knotters, so this is a bit new to me.  The manual really doesn't cover this problem in their troubleshooting section.