Explanation:
Too much fire. Better to cook it in another way.
If there is a marinade, the outside will burn faster due to the presence of sugars in the marinade. Also, when the outside burns and the inside is raw, it means the heat is too intense. It way overcooked the outside of the meat before it could heat up the inside. This is why if you try to cook a hunk of meat directly over a fire, the outside is burned and the inside is raw. Heat requires some time to penetrate the meat, and when the rate of cooking on the outside exceeds the rate that the inside heats up, the outside cooks faster than the inside.
To help solve this, set up 2 zones whenever grilling. One zone should be the hot zone where all the direct cooking happens. The other zone should be unheated, where no heat source directly continues to cook the food items. On the cool zone, the ambient heat when you close the lid will continue to cook the item gently.
