Re: 18hp 1960's Evinrude won't Start
When you try to start,do it with the lower unit at least half way submerged or you will burn out the impeller and blow up your engine.
If you have spark on only one cylinder,make sure that the ignition cable is well connected to the plug and the coils.
You may have to remove the flywheel and replace the coils. 48 year old coils tend to crack.While you have the flywheel off,you probably want to put in fresh condensers and points.Not neccesarily because they are bad now,but because it is a pain in the neck to remove the flywheel again and again.