if purchasing a car known as a lemon what are the risks

Obviously the risk is in buying a car with known problems that the previous owner couldn't fix in order to sell the car for a higher price. Unless you have the time and ability to fix it yourself it'll become a money pit for you.

It's a shot in the dark, either you will be very glad you purchased it or it will turn into a nightmare. I might be tempted to buy one just to see if I could fix it, but I like a challenge.