7XL Getting Hot

[giftacrylic]

I have an ext. G-Maxx with a 9920 and 7XL. I was running at 20/66 gearing for months (on 14 cells) with no problem. The motor started to heat up, changed it to 18/66. After 10 or so runs, within less than 5 minutes, the 7XL temps exceed 160F, the controller at 125 and batts at 125. On 16 cells at 15/66 gearing, motor temps exceed 160F after only a few minutes.

There is no binding on the drivetrain and I have reprogrammed the controller. What should the timing be set at?