Blue smoke usually has a lot to do with oil sludge built up between the case & crank over the many years,, ''like an old out board''.
Are you running the factory recommended oil gas mix now ?
I would put a quality fresh plug in it ''like an NGK'', & set the main back @ 1 turn, with a ''no alcohol'' / ''at least'' 32 -1 mix,, & run it for a good while.
Don't want to run it to lean & screetch that sucker.
Added,,
One of your above posts says it's ''never had gas in it''.
Does that mean it's never been run before, or never had gas ''left'' in it ??
Looking @ the pics of it,, ''fuel cap, starter handle ect.'',, it sure looks like it's been run before.
I would really like to see a good pic of the top of the piston with the plug out, or the exhaust port.
I