youdodat2 , I am glad you found the video helpful. There is no need to turn the fan while adjusting the stroke on a G Series pump. Some people will do it, as occasionally, the stoke adjusting knob can get in a very slight bind when the pump gear set is stationary. Firmly (but not forcefully) turning the knob in this situation will easily suffice. If the knob ever seems seriously stuck, it indicates other, more serious, issues that I would recommend a call to us at (800) 446-5328 to remedy. If you have any further questions, feel free to give us a call. Josh Krautkramer,Director R&D and Engineering, Agri-Inject