1989 90hp johnson, ran motor today and after about 10 mins. i shut it off an notice cyl. 2 and 4 were ice cold. So I assume it has no spark on these cyl. maybe why it seemed too idle a little rough.If it were just 1 cyl. I would guess maybe a coil but 2 cyl.s on the same side I am guessing something else?I haven't change the coils from 1 side too the other yet, what other things should I look at............