I have a 269 hayliner that I replaced. the clutch on the flywheel last cutting when it broke. Now when I start the pto it runs fine until I engage the knotters. then instantly shears pin. Looking at the needles they are not fully resetting and when I reset them manually it's fine again until the knotters are tripped. So I removed all hay and turned it over by hand and everything works fine. did this several times with no problems until I engage the PTO on the tractor and then the needles don't fully retract back and boom sheared pin. What is this and how to fix. Please. it did always shear a few pins before but not because of the needles not locking out. Help.