Last summer I noticed that when the temps were over 90 degrees after 5-6 hours of running my equipment I had difficulty starting them back up between jobs. I am starting to experience that again. Has anyone had this problem? Any help would be much appreciated. I run Stihl blowers and trimmers and John Deere ZTR 737 and 810. No problem with the 810 so far as it is new, but have already noticed it on the 737 and the blowers. Thanks.