13 runs great. Perfect throttle response. No bog (like my 11 had periodically). Holds 8300 - 8400 RPM in long steep pulls in deep snow (Carl's Clutching Kit). No oil pump adjustments unless dealer did it which I doubt. I am not going to do it either. It is getting enough oil as far as I can tell. If not, that is why I have the 4 year warranty.