I just bought a boat with an 1982 80hp Merc outboard and we were out on the weekend and the people in the back couldn't stand the fumes,burning there eyes. Is this normal when putting down the river. There is a hole that I believe was cut for better access to the bottom spark plug that we covered with a sticker but that shouldn't block any exhaust. Any ideas on how to fix this besides selling the boat. Thx