I do a lot of daytime mowing on my 4210 when it gets into the mid 80's and I have never noticed a "hot foot" problem, but I do use the cruise control for much of the mowing jobs. Since my yard is rather rough using the cruise also keeps my foot from bouncing around on the hydro pedal.
After every mowing job, I reverse up to the barn overhead door, raise the hood and remove the side panels while letting the engine cool down at idle. I take a few minutes to use my electric blower to clear off the grass clippings and weed chaff, I also slide out the radiator screen and blow it off along with any debris that may be on the radiator itself. Since JD recommends running at idle for a few minutes after sustained use, this is the ideal way for me to spend the time. Of course, the electric blower has a tag on it that says:
"FOLD THE ROPS" /forums/images/graemlins/grin.gif
Even in the hottest weather my temp gauge never goes over a quarter of the scale, I am wondering if that 4310 is overheating....