I agree with lineman49 about the oil. We had a 69 Johnson 9 1/2 that used at least a 32:1 ratio if not 24:1. It was a long time ago... but I remember getting a new outboard that used a 50:1 and thinking we were saving a lot of oil. You never say if you get a good stream of water? Sk8man is right a little junk can clog the lines or even just the intake (happened on my old i/o just inside the intake with zebra mussel shells). Good luck though... something about those old motors...