I took the carb apart and it was full of fine black particles! The primer was also. I cleaned it good and now I can prime it, leave the primer all the way out and it usually starts on one or two pulls. This black crud is from the internal flexible fuel line that was rotting inside the tank. It has a plastic tank that mounts on the engine. I had to wash it out with lots of hot water and replace the fuel lines that were rotted and full of crud. The crud had plugged the primer holes that feed the carb throat basically. All's good and I found a Johnson owner's manual for that year so I have starting instructions and service.
Thanks, Herb