repair Joh Deere 145 shutting off?

Hi
I have a John Deere modle #145 with a 22 hp Briggs engine. After starting it will run for about 5-10 min and then shut off and won't restart. If I leave it sit for about 30-45 min it will then restart and run until I finish mowing usually about 30-45 min. I have replaced the fuel filter and fuel pump and this didn't make any difference. Any help you can give is greeatly appreciated
Thanks
Tony