Brand new Exmark Lazer Z with 10 hours on it. 28hp Kohler, and 66" triton deck. Also running the Ultra Vac bagger. My Exmark struggles to engage the PTO, here are a couple situations: In the mornings I have to let it warm up for about 15 minutes, and even then to engage the PTO and keep the mower running I have to engage the PTO while pushing the throttle to wide open at the same time. Then it may stay running, but it struggles for a couple seconds. Or later in the day, after a couple hours of mowing, I can engage the PTO while its WFO, and it will keep running. But if I engage the PTO while the mower is moving, and WFO, then it will die. So I have to be stopped to get it engaged. Or I have found a good way to do it is to quickly engage, then disengage, then reengage the PTO, this works pretty good, but is only a 'patch' fix. These are on 45-50 degree mornings, and 60-65 degree afternoons. Is it just to cold, or should I be looking for another problem?