Remington RM360 just stops

I have a Remington RM360 made by Kohler (or maybe the other way around but both names are on mower). Last year the engine would just stop about an hour into cutting my lawn and it seems like its getting shorter each time I use it. I'm down to about 35 min until its stops running. I have to wait a day until it cools back down until I can start it again. Would this be a spark plug getting too hot kind of situation? Oil and gas are always full.

Any help would be appreciated

Thanks

Remington RM360 just stops