34 years sitting...I used wd40 in the cylinders, sprayed it in with the straw and tried to spread it all around in the cylinders.I sprayed once or twice a week for months..just letting it sit and soak...then spun it with a flywheel Turner and it broke free..sprayed more wd40 and rotated the engine some more..then new plugs, fresh gas from a can into the fuel pump then...
https://youtu.be/OSkDnAzu9w8