Horse refusing jumps and rushing?

i have a 7 year old anglo-arab and hez really good but he is the fastest horse evr. he is a great jumper but rushes over them and refuses alot especially red and bright coloured jumps. i try to make him work on the bit and he does it for about 5 sec and then puts his head up like a maniac. he went to a show and was only jumping 65cm and he refused it was really embarring and it was a red jump. please help