1985 125 HP Force, model # 1258X5A. Compression 140-145 on all 4 cylinders. It has new Champion UL18V spark plugs. Starts and idles on top 2 cylinders, 3&4 have no effect when grounded out. It has spark and gas to all 4 cylinders. I have switched coils and C-D boxes in every configuration I could think of. It still starts and idles on the top 2 cylinders. It will clear itself at WOT but it'll miss occasionally. The exhaust is blue with un-ignited fuel from the bottom 2 cylinders. I have read that others have had this problem and read their solutions, none of worked with this beast. Please help. Thanks