It almost sounds like the engine is running lean and overheating if you have to wait a while before it’ll restart. How do you know it’s running rich? By the smoke coming from the exhaust? Depending on the engine and the adjustments it has, you could be rich on the low speed needle and lean on the high speed or vice versa. What kind of engine? You mentioned a pull start. I’ve been out of the hobby for over a decade, but in my experience in the past, most engines that come with a ready to run aren’t of high quality and are usually difficult to tune and to keep running properly. The quality could have changed now though. Is this a brand new engine? Did you break it in properly?