I have a mercruiser 470 and it was running good....I put in new plugs and it ran good for a couple trips out, then toward the end of one boating trip it felt like it had kinda loping at high rpm around 4500....it wouldnt hold steady....now it wont really even stay over 4 grand consistantly and when you do hold it wide open it chokes slightly and even sometimes makes a popping noise like its popping back through the carb? Any ideas of the problem and how to fix?
