A lawn mower engine can get quite hot, especially when used for extended periods of time. The average temperature of a lawn mower engine is between 130 and 150 degrees Fahrenheit. However, some engines can get as hot as 200 degrees Fahrenheit. It is important to keep an eye on the temperature of your engine and make sure it does not exceed the manufacturer's recommended maximum temperature. If your engine does get too hot, it can damage the components and shorten the lifespan of your lawn mower. So, if you're mowing your lawn for more than an hour, be sure to take a break every so often to let your engine cool down. Otherwise, you could be doing more harm than good.