[Al Skierkiewicz]

Steve,
I am guessing that the FP motor and tranny is for turning the top arm, is that correct? If so, I am also guessing that you have not accounted for the friction at the turning point. With an 8 lb tetra at the end, the turning friction must be enormous. You may need to put a heavy duty bearing at that point to reduce the friction. I would be careful as you troubleshoot as some teams have reported stressing the FP gearbox to the breaking point. You might also consider some counter weight of some type to balance the load at the top of the arm. Springs or surgical tubing works well in these apps. Pictures would help a great deal.