Just bought a nice champ with a 175 merc efi. Good compression across all 6 cylinders. Turns a 25 trophy to 5600 rpms and jumps out of the hole. Seems to be a strong engine. I am torn as whether to remove the oil injection system and premix or not. I found out from a local mechanic it would cost me a $125.00 to remove it. Anyone do it with a efi and what were the results. Of course Don's opinion will be valued, thanks.