Try to hold the temperature steady at 240F and make sure that you have a nice, light blue smoke coming out of the top. Cooters are tough, so they need to be smoked low and slow. You might want to baste that cooter with some apple cider vinegar every hour for about eight hours. When the cooter seems to be kind of springy and flexible, you'll know that it's about finished. It needs an internal temp of about 200. You were smoking this cooter with fruitwood like apple or cherry, right? Because hickory wood is too strong a wood to smoke a cooter from what I have read on American BBQing sites. Make sure to coat that cooter with a heavy slathering of barbeque sauce about ten minutes before you are ready to pull it off of the BBQ. Let that cooter rest for at least a half hour before eating the cooter.