The motor whines loudly and was definitely straining. I test cooked one 5 pound baby chicken and made sure it was centered and balanced on the rod. There is NO WAY this motor can handle the maximum it says it can. 
The mount it comes with is flimsy and bends easily.  When I attached the motor the mount bent backwards and was not properly centered...I straightened it out but as it turned bent the mount backwards again like it was about to take a nap.  Overall it is definitely not worth the price I paid and it will surely die out before it's expected usable service life.. Bottom line...Weber put most of their effort in designing the plastic case that covers the motor and used a thin gauge metal mount that isn't consistent with their grills....