...generally, if it would smoke when first started, then not after..the valve seals are not right..
..when those seals fail, oil leaks down into the cylinder after the engine is stopped...
..it sits atop the piston, then when it's started the next time, all that collected oil burns off....
..wouldn't take very much of a faulty seal to cause this initial smoke...and it wouldn't take a lot of oil either...
peace