I'd think that tightening the tension on the billhook a 1/4 turn or less at a time you  should be able to get her going. I'm sure you checked for rough spots on the billhook. As to the color, I had to buy two new needles from Agco for my 620 about 3 yrs ago and they were the same gray color.

Last week My son and Grandson put up just under 1000 bales of alfalfa/timothy. Cut it a week ago last sunday and the weatherman said no rain 'til friday. By Monday noon there was chance of thunderstorms every day of the week. Got about 300 bales worth rained on, maybe 1/4&quot;, the rest went good. Always good to get the first cutting in the barn, those long stems and weeds don't dry so well!  <!-- s:wink: --><img src="{SMILIES_PATH}/icon_wink.gif" alt=":wink:" title="Wink" /><!-- s:wink: --> 
Larry Coltrin