How do I work with someone I can't stand all summer?

I'm his crew chief but I find him boorish, and irresponsible plus he seems to have this inability to think through the consequences of his actions. He doesn't like listening to me even though I have 4 years experience. Therefore, I have to stand over his shoulder badgering him all the time to make sure he doesn't do anything dangerous (we're operating heavy lawn equipment). My boss doesn't have enough money to spend time training someone else. I love my boss and my job. How do I put up with this idiot the whole summer when we work 10 hours a day together